U.S. patent number RE47,863 [Application Number 13/560,180] was granted by the patent office on 2020-02-18 for non-ferromagnetic amorphous steel alloys containing large-atom metals.
This patent grant is currently assigned to University of Virginia Patent Foundation. The grantee listed for this patent is Xiaofeng Gu, S. Joseph Poon, Gary J. Shiflet. Invention is credited to Xiaofeng Gu, S. Joseph Poon, Gary J. Shiflet.
![](/patent/grant/RE047863/USRE047863-20200218-D00000.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00001.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00002.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00003.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00004.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00005.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00006.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00007.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00008.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00009.png)
![](/patent/grant/RE047863/USRE047863-20200218-D00010.png)
View All Diagrams
United States Patent |
RE47,863 |
Shiflet , et al. |
February 18, 2020 |
Non-ferromagnetic amorphous steel alloys containing large-atom
metals
Abstract
The present invention relates to novel non-ferromagnetic
amorphous steel alloys represented by the general formula:
Fe--Mn-(Q)-B-M, wherein Q represents one or more elements selected
from the group consisting of Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb,
Dy, Ho, Er, Tm, Yb and Lu, and M represents one or more elements
selected from the group consisting of Cr, Co, Mo, C and Si.
Typically the atomic percentage of the Q constituent is 10 or less.
An aspect is to utilize these amorphous steels as coatings, rather
than strictly bulk structural applications. In this fashion any
structural metal alloy can be coated by various technologies by
these alloys for protection from the environment. The resultant
structures can utilize surface and bulk properties of the amorphous
alloy.
Inventors: |
Shiflet; Gary J.
(Charlottesville, VA), Poon; S. Joseph (Charlottesville,
VA), Gu; Xiaofeng (Wuxi, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Shiflet; Gary J.
Poon; S. Joseph
Gu; Xiaofeng |
Charlottesville
Charlottesville
Wuxi |
VA
VA
N/A |
US
US
CN |
|
|
Assignee: |
University of Virginia Patent
Foundation (Charlottesville, VA)
|
Family
ID: |
69492578 |
Appl.
No.: |
13/560,180 |
Filed: |
July 27, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
10559002 |
|
|
|
|
|
PCT/US2004/016442 |
May 25, 2004 |
|
|
|
|
60638259 |
Dec 22, 2004 |
|
|
|
|
60546761 |
Feb 23, 2004 |
|
|
|
|
60513612 |
Oct 23, 2003 |
|
|
|
|
60475185 |
Jun 2, 2003 |
|
|
|
Reissue of: |
11313595 |
Dec 21, 2005 |
7763125 |
Jul 27, 2010 |
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C
33/003 (20130101); C22C 45/02 (20130101); C22C
45/02 (20130101) |
Current International
Class: |
C22C
45/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1321056 |
|
Nov 2001 |
|
CN |
|
0713925 |
|
May 1996 |
|
EP |
|
53-057119 |
|
May 1978 |
|
JP |
|
54-048637 |
|
Apr 1979 |
|
JP |
|
07331396 |
|
Dec 1995 |
|
JP |
|
09268354 |
|
Oct 1997 |
|
JP |
|
11-186020 |
|
Jul 1999 |
|
JP |
|
2000054089 |
|
Feb 2000 |
|
JP |
|
2000073148 |
|
Mar 2000 |
|
JP |
|
2000234461 |
|
Aug 2000 |
|
JP |
|
WO 98/22629 |
|
May 1998 |
|
WO |
|
Other References
V Ponnambalam el al., "Fe-Based Bulk Metallic Glasses with Diameter
Thickness Larger than One Centimeter", Journal of Materials
Research, 2004, p. 1320-1323, vol. 19, No. 5, Materials Research
Society. cited by examiner .
A. Inoue et al., "Synthesis and Properties of Ferromagnetic Bulk
Amorphous Alloys", in Bulk Metallic Glasses, edited by W.L. Johnson
et al., Materials Research Society Proceedings, 1999, p. 251-262,
vol. 554, Warrendale, PA. cited by applicant .
S. Pang et al., "New Fe-Cr-Mo-(Nb,Ta)-C-B Alloys with High Glass
Forming Ability and Good Corrosion Resistance", Materials
Transactions, 2001, p. 376, vol. 42, No. 2, The Japan Institute of
Metals, Japan. cited by applicant .
H. Fukumura et al., "(Fe, Co)-(Hf, Nb)-B Glassy Thick Sheet Alloys
Prepared by a Melt Clamp Forging Method", Materials Transactions,
2001, p. 1820, vol. 42, No. 8, The Japan Institute of Metals,
Japan. cited by applicant .
T. Egami, "Universal Criterion for Metallic Glass Formation",
Materials Science and Engineering A, 1997, p. 261-267, vol.
226-228, Elsevier Science S.A. cited by applicant .
A. Inoue et al. "Formation and Functional Properties of Fe-Based
Bulk Glassy Alloys", Materials Transactions, 2001, p. 970, vol. 42,
No. 6, The Japan Institute of Metals, Japan. cited by applicant
.
V. Ponnambalam et al., "Synthesis of iron-based bulk metallic
glasses as nonferromagnetic amorphous steel alloys", Applied
Physics Letter, 2003, p. 1131-1133, vol. 83, No. 6, American
Institute of Physics. cited by applicant .
K. Hasimoto et al., "Extremely Corrosion-Resistant Bulk Amorphous
Alloys", Materials Science Forum, 2001, p. 1-8, vol. 377, Trans
Tech Publications, Switzerland. cited by applicant .
O. Beckman et al., "Low Field Simultaneous AC and DC Magnetization
Measurements of Amorphous (Fe0.20Ni0.80)75P16B6AI3 and
(Fe0.68Mn0.32)75P16B6AI3", Physica. Scripta., 1982, p. 676-678,
vol. 25. cited by applicant .
V. Ponnambalam et al., "Fe-Based Bulk Metallic Glasses with
Diameter Thickness Larger than One Centimeter", Journal of
Materials Research, 2004, p. 1320-1323, vol. 19, No. 5, Materials
Research Society. cited by applicant .
P. Hess et al., "Indentation Fracture Toughness of Amorphous
Steel", Journal of Materials Research, 2005, p. 783-786, vol. 20,
No. 4, Materials Research Society. cited by applicant .
V. Ponnambalam et al., "Fe-Mn-Cr-Mo-(Y,Ln)-C-B (Ln =Lanthanides)
Bulk Metallic Glasses as Formable Amorphous Steel Alloys", Journal
of Materials Research, 2004, p. 3046-3052, vol. 19, No. 10,
Materials Research Society. cited by applicant .
Z.P. Lu et al., "Structural Amorphous Steels", Physical Review
Letters, 2004, p. 245503-1-245503-4, vol. 92, No. 24, The American
Physical Society. cited by applicant .
R.D. Conner et al., "Mechanical Properties of
Zr57Nb5Al10Cu15.4Ni12.6 Metallic Glass Matrix Particulate
Composites", Journal of Materials Research, 1999, p. 3292-3297,
vol. 14, No. 8, Materials Research Society. cited by applicant
.
C.C. Hays et al., "Microstructure Controlled Shear Band Pattern
Formation and Enhanced Plasticity of Bulk Metallic Glasses
Containing in Situ Formed Ductile Phase Dendrite Dispersions",
Physical Review Letters, 2000, p. 2901-2904, vol. 84, No. 13, The
American Physical Socieety. cited by applicant .
F. Szuecs et al., "Mechanical Properties of
Zr56.2Ti13.8Nb5.06Cu6.9Ni5.6Be12.5 Ductile Phase Reinforced Bulk
Metallic Glass Composite", Acta Materialia, 2001, p. 1507-1513, No.
49, Elsevier Science Ltd. cited by applicant .
U. Kuhn et al., "ZrNbCuNiAl Bulk Metallic Glass Matrix Composites
Containing Dendritic BCC Phase Precipitates", Applied Physics
Letters, 2002, p. 2478-2480, vol. 80, No. 14, American Institute of
Physics. cited by applicant .
C. Fan et al., "Metallic Glass Matrix Composite with Precipitated
Ductile Reinforcement", Applied Physics Letters, 2002, p.
1020-1022, vol. 81, No. 6, American Institute of Physics. cited by
applicant .
R.T. Ott et al., "Structure and Properties of Zr-Ta-Cu-Ni-Al Bulk
Metallic Glasses and Metallic Glass Matrix Composites", Journal of
Non-Crystalline Solids, 2003, p. 158-163, vol. 317, Elsevier
Science B.V, cited by applicant .
L.Q. Xing et al., "Relation Between Short-Range Order and
Crystallization Behavior in Zr-Based Amorphous Alloys", Applied
Physics Letters, 2000, p. 1970-1972, vol. 77, No. 13, American
Institute of Physics. cited by applicant .
Y.K. Xu et al., "Ceramics Particulate Reinforced Mg65Cu20Zn5Y10
Bulk Metallic Glass Composites", Scripta Materialia, 2003, p.
843-848, No. 49, Elsevier Science Ltd. cited by applicant .
H. Ma et al., "Mg-Based Bulk Metallic Glass Composites with
Plasticity and High Strength", Applied Physics Letters, 2003, p.
2793-2795, vol. 83, No. 14, American Institute of Physics. cited by
applicant .
M. Widom et al., "Stability of Fe-Based Alloys with Structure Type
C6Cr23", Journal of Materials Research, 2005, p. 237-242, vol. 20,
No. 1, Materials Research Society. cited by applicant .
S.V. Nair et al., "Toughening Behavior of a Two-Dimensional SiC/SiC
Woven Composite At Ambient Temperature: I, Damage Initiation and
R-Curve Behavior", Journal of the American Ceramic Society, 1998,
p. 1149-1156, vol. 81, No. 5. cited by applicant .
S. Pang et al., "New Fe-Cr-Mo-(Nb,Ta)-C-B Alloys with High Glass
Forming Ability and Good Corrosion Resistance", Materials
Transactions, 2001, p. 376-379, vol. 42, No. 2, The Japan Institute
of Metals, Japan. cited by applicant .
H. Fukumura et al., "(Fe, Co)-(Hf, Nb)-B Glassy Thick Sheet Alloys
Prepared by a Melt Clamp Forging Method", Materials Transactions,
2001, p. 1820-1822, vol. 42, No. 8, The Japan Institute of Metals,
Japan. cited by applicant .
Inoue et al. "Formation and Functional Properties of Fe-Based Bulk
Glassy Alloys", Materials Transactions, 2001, p. 970-978, vol. 42,
No. 6, The Japan Institute of Metals, Japan. cited by
applicant.
|
Primary Examiner: Vincent; Sean E
Attorney, Agent or Firm: Decker; Robert J. Dorsey &
Whitney LLP
Government Interests
US GOVERNMENT RIGHTS
This invention was made with United States Government support under
ONR Grant No. N00014-01-1-10961 awarded by the Defense Advance
Research Projects Agency/Office of Naval Research. The United
States Government has certain rights in the invention.
Parent Case Text
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims priority under 35 USC .sctn. 119(e) to U.S.
Provisional Application Ser. Nos. 60/638,259, filed Dec. 22, 2004,
and is a Continuation-in-part application of U.S. application Ser.
No. 10/559,002, filed Nov. 30, 2005 now U.S. Pat. No. 7,517,415,
entitled "Non-ferromagnetic Amorphous Steel Alloys Containing
Large-Atom Metals," which is a national stage filing of
International Application No. PCT/US2004/016442, filed on May 25,
2004, which claims priority under 35 USC .sctn. 119(e) to U.S.
Provisional Application Ser. Nos. 60/475,185, filed Jun. 2, 2003,
60/513,612, filed Oct. 23, 2003 and 60/546,761, filed Feb. 23,
2004, all of the above-mentioned disclosures of which are hereby
incorporated by reference herein in their entirety.
Claims
We claim:
1. An amorphous alloy represented by the formula:
Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 and wherein for
a test duration said alloy is exposed to an environment having a
designated pH level, said alloy is determined to have a
differential voltage, V, wherein differential voltage, V, equals
E.sub.pit-E.sub.oc, wherein E.sub.pit is pitting potential and
E.sub.oc is open circuit potential, wherein: said alloy has a
voltage differential, V, that is determined to have at least one of
the following magnitudes: if said PH level is equal to about 1.0,
then V is equal to about 0.710 if said PH level is equal to about
6.5, then V is equal to about 0.883 and if said PH level is equal
to about 11.0, then V is equal to about 1.129.
2. The alloy of claim 1, wherein said alloy is processable into
bulk amorphous samples of less than about 0.1 mm in thickness in
its minimum dimension.
3. The alloy of claim 1, wherein said alloy is processable into
bulk amorphous samples of at least about 0.1 mm in thickness in its
minimum dimension.
4. The alloy of claim 1, wherein said alloy is processable into
bulk amorphous samples of at least about 0.5 mm in thickness in its
minimum dimension.
5. The alloy of claim 1, wherein said alloy is processable into
bulk amorphous samples of at least about 1 mm in thickness in its
minimum dimension.
6. The alloy of claim 1, wherein said alloy is processable into
bulk amorphous samples of at least about 5 mm in thickness in its
minimum dimension.
7. The alloy of claim 1, wherein said alloy is processable into
bulk amorphous samples of at least about 10 mm in thickness in its
minimum dimension.
8. The alloy of claim 1, wherein said alloy is processable into
bulk amorphous samples of at least about 12 mm in thickness in its
minimum dimension.
9. The alloy of claim 1, wherein said alloy is processable into an
article.
10. The alloy of claim 9, wherein said processed article is
provided by at least one of the following processing methods: melt
spinning, atomization, spray forming, scanning-beam forming,
plastic forming, casting, and compaction.
11. The alloy of claim 1, wherein said alloy is processable into a
coating.
12. The alloy of claim 11, wherein said processed coating is
provided by at least one of the following processing methods: melt
spinning, atomization, spray forming, scanning-beam forming,
plastic forming, casting, and compaction.
13. The alloy of claim 11, wherein said coating comprises corrosion
resistant type coating and/or wear-resistant type coating.
14. The alloy of claim 11, wherein said coating is disposed on a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane walls and frames, ship
walls, submarine walls, vehicle walls, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, hand tools and medical implants and
devices, cell phone and PDA casings, housings, and interior
components, electronics and computer casings, housings and interior
components.
15. The alloy of claim 1, wherein said alloy is processable into a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, ship walls, submarine walls,
vehicle walls, armor penetrators, projectiles, protection armors,
rods, train rails, cable armor, power shaft, and actuators, hand
tools and medical implants and devices, cell phone and PDA casings,
housings, and interior components, electronics and computer
casings, housings and interior components.
16. The alloy of claim 1, wherein said test duration is less than
about 1 hour.
17. The alloy of claim 1, wherein said test duration is about 1
hour.
18. The alloy of claim 1, wherein said test duration is greater
than about 1 hour.
19. An amorphous alloy represented by the formula:
Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6 and wherein for a test
duration said alloy is exposed to an environment having a
designated pH level, said alloy is determined to have a
differential voltage, V, wherein differential voltage, V, equals
E.sub.pit-E.sub.oc, wherein E.sub.pit is pitting potential and
E.sub.oc is open circuit potential, wherein: said alloy has a
voltage differential, V, that is determined to have at least one of
the following magnitudes: if said PH level is equal to about 1.0,
then V is equal to about 0.087; if said PH level is equal to about
6.5, then V is equal to about 0.244; and if said PH level is equal
to about 11.0, then V is equal to about 0.777.
20. The alloy of claim 19, wherein said alloy is processable into
bulk amorphous samples of less than about 0.1 mm in thickness in
its minimum dimension.
21. The alloy of claim 19, wherein said alloy is processable into
bulk amorphous samples of at least about 0.1 mm in thickness in its
minimum dimension.
22. The alloy of claim 19, wherein said alloy is processable into
bulk amorphous samples of at least about 0.5 mm in thickness in its
minimum dimension.
23. The alloy of claim 19, wherein said alloy is processable into
bulk amorphous samples of at least about 1 mm in thickness in its
minimum dimension.
24. The alloy of claim 19, wherein said alloy is processable into
.[.hulk.]. .Iadd.bulk .Iaddend.amorphous samples of at least about
5 mm in thickness in its minimum dimension.
25. The alloy of claim 19, wherein said alloy is processable into
bulk amorphous samples of at least about 10 mm in thickness in its
minimum dimension.
26. The alloy of claim 19, wherein said alloy is processable into
bulk amorphous samples of at least about 12 mm in thickness in its
minimum dimension.
27. The alloy of claim 19, wherein said alloy is processable into
an article.
28. The alloy of claim 27, wherein said processed article is
provided by at least one of the following processing methods: melt
spinning, atomization, spray forming, scanning-beam forming,
plastic forming, casting, and compaction.
29. The alloy of claim 19, wherein said alloy is processable into a
coating.
30. The alloy of claim 29, wherein said processed coating is
provided by at least one of the following processing methods: melt
spinning, atomization, spray forming, scanning-beam forming,
plastic forming, casting, and compaction.
31. The alloy of claim 29, wherein said coating comprises corrosion
resistant type coating and/or wear-resistant type coating.
32. The alloy of claim 29, wherein said coating is disposed on a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane walls and frames, ship
walls, submarine walls, vehicle walls, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, hand tools and medical implants and
devices, cell phone and PDA casings, housings, and interior
components, electronics and computer casings, housings and interior
components.
33. The alloy of claim 19, wherein said alloy is processable into a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, ship walls, submarine walls,
vehicle walls, armor penetrators, projectiles, protection armors,
rods, train rails, cable armor, power shaft, and actuators, hand
tools and medical implants and devices, cell phone and PDA casings,
housings, and interior components, electronics and computer
casings, housings and interior components.
34. The alloy of claim 19, wherein said test duration is less than
about 1 hour.
35. The alloy of claim 19, wherein said test duration is about 1
hour.
36. The alloy of claim 19, wherein said test duration is greater
than about 1 hour.
.Iadd.37. An iron-based bulk-solidifying amorphous alloy comprising
at least four elements including Fe, and having the formula
Fe--Mn--Cr--Mo--(C, B)-Q, where Q is a large-atom element selected
from the group consisting of Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb,
Dy, Ho, Er, Tm, Yb, and Lu, an amount of Mn is from 10 to 12 atomic
%, an amount of chromium is from 0 to 16 atomic %, an amount of Mo
is from 8 to 16 atomic %, an amount of (C, B) is greater than 18
atomic %, with an amount of C being at least 13 atomic % and an
amount of B being at least 5 atomic %, and an amount of Q is
greater than zero and less than or equal to 3 atomic %, and the
bulk-solidifying amorphous alloy is non-ferromagnetic at ambient
temperature..Iaddend.
.Iadd.38. The bulk-solidifying amorphous alloy of claim 37, wherein
an amount of Fe is at least 45 atomic %..Iaddend.
.Iadd.39. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a magnetic transition
temperature below ambient temperature..Iaddend.
.Iadd.40. The bulk-solidifying amorphous alloy of claim 37, wherein
the large-atom element is Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or
combinations thereof..Iaddend.
.Iadd.41. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a microhardness in the
range of about 1000-1300 DPN..Iaddend.
.Iadd.42. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a fracture toughness in a
range of about 3 to 4 GPa..Iaddend.
.Iadd.43. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a Young's modulus in a
range of about 180-210 GPa..Iaddend.
.Iadd.44. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a bulk modulus in a range
of about 140-190 GPa..Iaddend.
.Iadd.45. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a glass transition
temperature of about 530.degree. C. or greater..Iaddend.
.Iadd.46. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a reduced glass
temperature of about 0.58 or greater..Iaddend.
.Iadd.47. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a supercooled liquid
region of about 30.degree. C. or greater..Iaddend.
.Iadd.48. The bulk-solidifying amorphous alloy of claim 37, wherein
the bulk-solidifying amorphous alloy has a liquidus onset
temperature in a range from about 1065.degree. C. to 1105.degree.
C..Iaddend.
.Iadd.49. The bulk-solidifying amorphous alloy of claim 37, wherein
the alloy further comprises 2 atomic % or less of one or elements
selected from Ti, Zr, Hf, Nb, V, Ta, W, Al, Ga, In, Sn, Si, Ge, and
Sb..Iaddend.
Description
BACKGROUND OF THE INVENTION
Bulk-solidifying amorphous metal alloys (a.k.a. bulk metallic
glasses) are those alloys that can form an amorphous phase upon
cooling the melt at a rate of several hundred degrees Kelvin per
second or lower. Most of the prior amorphous metal alloys based on
iron (i.e., those that contain 50 atomic percent or higher iron
content) are designed for magnetic applications. The Curie
temperatures are typically in the range of about 200-300.degree. C.
Furthermore, these previously described amorphous iron alloys are
obtained in the form of cylinder-shaped rods, usually three
millimeters or smaller in diameter, as well as sheets less than one
millimeter in thickness.
Recently, a class of bulk-solidifying iron-based amorphous metals
have been described that exhibit suppressed magnetism, relative to
conventional compositions, while still achieving acceptable
processibility of the amorphous metal alloys and maintaining
superior mechanical properties and good corrosion resistance
properties. These alloys are described in U.S. patent application
Ser. No. 10/364,123 and PCT Patent Application No. PCT/US03/04049,
and both having a filing date of Feb. 11, 2003 (both of these
disclosures of which are hereby incorporated by reference herein in
their entirety). These previously described amorphous alloys, which
are non-ferromagnetic at ambient temperature, are multicomponent
systems that contain about 50 atomic percent iron as the major
component. The remaining composition combines suitable mixtures of
metalloids and other elements selected mainly from manganese,
chromium, and refractory metals. In addition these amorphous alloys
exhibited improved processibility relative to previously disclosed
bulk-solidifying iron-based amorphous metals, and this improved
processibility is attributed to the high reduced glass temperature
Trg (e.g., 0.6 to 0.63) and large supercooled liquid region
(.DELTA.Tx) (e.g., about 50-100.degree. C.) of the alloys. However,
the largest diameter size of amorphous cylinder samples that could
be obtained using these alloys was approximately 4 millimeters.
There is a strong desire for bulk-solidifying iron-based amorphous
alloys, which are non-ferromagnetic at ambient temperature and
exhibit a higher degree of processibility than previously disclosed
alloys. The present invention relates to amorphous steel alloys
that comprise large atom inclusions to provide a non-ferromagnetic
(at ambient temperature) bulk-solidifying iron-based amorphous
alloys with enhanced glass formability. Large atoms are
characterized by an atom size ratio of .about.1.2 between the large
atom and iron atom, and their inclusion in the alloy significantly
improves the processibility of the resulting amorphous steel alloy,
resulting in sample dimensions that reach 12 millimeters or larger
(0.5 inch) in diameter thickness.
SUMMARY OF VARIOUS EMBODIMENTS OF THE INVENTION
One embodiment of the present invention is directed to novel
non-ferromagnetic amorphous steel alloys represented by the general
formula: Fe--Mn--Cr--Mo--B-M-X--Z-Q wherein M represents one or
more elements selected from the group consisting of Al, Ga, In, Sn,
Si, Ge and Sb; X represents one or more elements selected from the
group consisting of Ti, Zr, Hf, Nb, V, W and Ta; Z is an element
selected from the group consisting of C or Ni; and Q represents one
or more large-atom metals. Typically, the total amount of the Q
constituent is 3 atomic percents or less. In one embodiment the
non-ferromagnetic amorphous steel alloy is represented by the
general formula: Fe--Mn--Cr--Mo-(Q)-C--(B) and in another
embodiment the alloy is represented by the general formula:
Fe--Mn--(Q)-B--(Si), wherein the elements in parentheses are minor
components. In accordance with one embodiment the improved
non-ferromagnetic amorphous steel alloys of the present invention
are used to form articles of manufacture.
An aspect of an embodiment of the present invention provides an
amorphous alloy represented by the formula:
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6
and wherein for a test duration the alloy is exposed to an
environment having a designated pH level. The alloy is determined
to have a differential voltage, V, wherein differential voltage, V,
equals E.sub.pit-E.sub.oc, wherein E.sub.pit is pitting potential
and E.sub.oc is open circuit potential, wherein:
the alloy has a voltage differential, V, that is determined to have
at least one of the following magnitudes: if the PH level is equal
to about 1.0, then V is equal to about 0.202; if the PH level is
equal to about 6.5, then V is equal to about 0.782; and if the PH
level is equal to about 11.0, then V is equal to about 1.263.
Further, the test duration can be less than about 1 hour, about an
hour or greater than an hour.
An additional aspect of an embodiment of the present invention
provides an amorphous alloy represented by the formula:
Fe.sub.48Cr.sub.15Mo.sub.14ER.sub.2C.sub.15B.sub.6
and wherein for a test duration the alloy is exposed to an
environment having a designated pH level. The alloy is determined
to have a differential voltage, V, wherein differential voltage, V,
equals E.sub.pit-E.sub.oc, wherein E.sub.pit is pitting potential
and E.sub.oc is open circuit potential, wherein:
the alloy has a voltage differential, V, that is determined to have
at least one of the following magnitudes: if the PH level is equal
to about 1.0, then V is equal to about 0.710 if the PH level is
equal to about 6.5, then V is equal to about 0.883 and if the PH
level is equal to about 11.0, then V is equal to about 1.129.
Further, the test duration can be less than about 1 hour, about an
hour or greater than an hour.
Still yet, an aspect of an embodiment of the present invention
provides an amorphous alloy represented by the formula:
Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6
and wherein for a test duration the alloy is exposed to an
environment having a designated pH level. The alloy is determined
to have a differential voltage, V, wherein differential voltage, V,
equals E.sub.pit-E.sub.oc, wherein E.sub.pit is pitting potential
and E.sub.oc is open circuit potential, wherein:
the alloy has a voltage differential, V, that is determined to have
at least one of the following magnitudes: if the PH level is equal
to about 1.0, then V is equal to about 0.087; if the PH level is
equal to about 6.5, then V is equal to about 0.244; and if the PH
level is equal to about 11.0, then V is equal to about 0.777.
Further, the test duration can be less than about 1 hour, about an
hour or greater than an hour.
These and other aspects of the disclosed technology and systems,
along with their advantages and features, will be made more
apparent from the description, drawings and claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated into and form a
part of the instant specification, illustrate several aspects and
embodiments of the present invention and, together with the
description herein, serve to explain the principles of the
invention. The drawings are provided only for the purpose of
illustrating select embodiments of the invention and are not to be
construed as limiting the invention.
FIG. 1 illustrates an x-ray diffraction pattern from exemplary
sample pieces (each of total mass about 1 gram) obtained by
crushing as-cast rods of an amorphous steel alloy of the present
invention (DARVA-Glass 101).
FIG. 2 illustrates a differential thermal analysis plot obtained at
scanning rate of 10.degree. C./min showing glass transition,
crystallization, and melting in the present invention exemplary
amorphous steel alloys of DARVA-Glass101. FIG. 2A represents the
plot for the composition
Fe.sub.65-x-yMn.sub.10Cr.sub.4Mo.sub.xQ.sub.yC.sub.15B.sub.6, and
FIG. 2B represents the plot for the composition
Fe.sub.64-x-yCr.sub.15Mo.sub.xQ.sub.yC.sub.15B.sub.6, wherein Q is
Y or a lanthanide element.
FIG. 3A illustrates an x-ray diffraction pattern for
Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 obtained by
using crushed pieces (mass .about.1 gram) from an injection-cast 10
mm-diameter rod. FIG. 3B represents a camera photo of a 10 mm-(top)
and 12 mm-diameter (bottom) glassy rods as well as the sectioned
surface of a small segment fractured from a 12 mm-diameter glassy
rod.
FIGS. 4A and 4B illustrate x-ray diffraction pattern from exemplary
samples of DARVA-Glass1 (FIG. 4A) and DARVA-Glass101 (FIG. 4B) for
the same annealing time and temperature.
FIG. 5A & 5B illustrate differential thermal analysis plots
obtained at scanning rate of 10.degree. C./min showing glass
transition, crystallization, and melting in several exemplary
amorphous steel alloys of DARVA-Glass201. The partial trace is
obtained upon cooling.
FIG. 6 illustrates an x-ray diffraction pattern from exemplary
sample pieces each of total mass about 1 gm obtained by crushing
as-cast rods of the present invention DARVA-Glass101 amorphous
steel alloy.
FIG. 7 graphically provides Open Circuit Potential (OCP) and Linear
Sweep Polarization (LP) for alloy
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6.
FIG. 8 graphically provides cyclic potential (CP) results for alloy
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6 in basic,
neutral and acidic solutions.
FIGS. 9A, 9B, 9C and 9D provide depictions of optical microscope
images of sample surface for alloy
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6 in basic,
neutral and acidic solutions following CP tests.
FIG. 10 provides a graphical Open Circuit Potential (OCP) and
Linear Sweep Polarization (LP) for alloy
Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6.
FIG. 11 provides a graphical Cyclic potential (CP) results for
alloy Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 in basic,
neutral and acidic solutions.
FIGS. 12A and 12B depict depicts optical microscope images of
sample surface for alloy
Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 before and after
CP at pH 6.5.
FIG. 13 provides a graphical Open Circuit Potential (OCP) and
Linear Sweep Polarization (LP) for alloy
Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6.
FIG. 14 provides a graphical Cyclic potential (CP) results for
alloy Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6 in basic, neutral
and acidic solutions.
FIGS. 15A and 15B depict Optical microscope images of sample
surface for alloy Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6 before
and after CP at pH 6.5.
FIGS. 16A and 16B graphically provide pitting potential and the
difference between pitting potential and open circuit potential vs
pH for the three different amorphous steels discussed in this
disclosure. Also compared with some common metal elements.
FIG. 17 provides a bar graph illustrating the loss of material per
year because of corrosion for a variety of elements at various pH
levels.
DETAILED DESCRIPTION OF EMBODIMENTS
Definitions
In describing and claiming the invention, the following terminology
will be used in accordance with the definitions set forth
below.
As used herein, the term "reduced glass temperature (Trg)" is
defined as the glass transition temperature (Tg) divided by the
liquidus temperature (Tl) in K.
As used herein, the term "supercooled liquid region (.DELTA.Tx)" is
defined as crystallization temperature minus the glass transition
temperature.
As used herein, the term "large atom metals" refers to elements
having an atom size ratio of approximately 1.2 or greater relative
to the iron atom. These include the elements Sc, Y, Ce, Pr, Nd, Pm,
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
As used herein, the term "iron-based alloy" refers to alloys
wherein iron constitutes a major component of the alloy. Typically,
the iron-based amorphous alloys of the present invention have an Fe
content of approximately 50%, however, the Fe content of the
present alloys may comprise anywhere from 35% to 65% iron.
As used herein, the term "amorphous alloy" is intended to include
both completely amorphous alloys (i.e. where there is no ordering
of molecules), as well as partially crystalline alloys containing
crystallites that range from nanometer to the micron scale in
size.
Embodiments
The present invention relates to non-ferromagnetic (at ambient
temperature) bulk-solidifying iron-based amorphous alloys that have
been prepared using large atom inclusions to enhance the glass
formability of the alloy. In one embodiment the improved
non-ferromagnetic (at ambient temperature) bulk-solidifying
iron-based amorphous alloys of the present invention are completely
amorphous. Large atoms, as the term is used herein, are
characterized as having an atom size ratio of approximately 1.3 or
greater relative to iron. Inclusion of such large atoms, including
ytrium and the lanthanide elements, in non-ferromagnetic iron-based
amorphous alloys significantly improves the processibility of the
resulting amorphous steel alloy. More particularly, in one
embodiment, iron-based amorphous alloys, comprising at least 45%
iron, are prepared using commercial grade material to create alloys
that can be processed into cylinder samples having a diameter of 5
millimeters or greater. In one embodiment iron-based amorphous
alloys, comprising at least 45% iron, are prepared using commercial
grade material to create alloys that can be processed into cylinder
samples having a diameter of 7 millimeters or greater.
The alloys of the present invention represent a new class of
castable amorphous steel alloys for non-ferromagnetic structural
applications, wherein the alloys exhibit enhanced processibility,
(relative to previously disclosed bulk-solidifying iron-based
amorphous alloys) magnetic transition temperatures below ambient
temperatures, mechanical strengths and hardness superior to
conventional steel alloys, and good corrosion resistance.
Furthermore, since the synthesis-processing methods employed by the
present invention do not involve any special materials handling
procedures, they are directly adaptable to low-cost industrial
processing technology.
Introduction of large atoms into amorphous steel alloys leads to
the destabilization of crystal phase due to severe atomic level
stress, resulting in the (relative) stabilization of the amorphous
phase instead. Additionally, the large-atom and metalloid elements
employed in the present invention alloys exhibit large negative
heats of formation and these two groups of atoms associate strongly
in the liquid state to form a reinforced structure that further
stabilizes the glass. In accordance with one embodiment an
iron-based amorphous alloy with enhanced glass formability
properties is prepared comprising one or more large-atom elements
selected from the group consisting of Sc, Y, Ce, Pr, Nd, Pm, Sm,
Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. In one embodiment the
large-atom element is selected from the group consisting of Y, Gd,
Tb, Dy, Ho, Er, Tm, Yb and Lu.
Several classes of non-ferromagnetic ferrous-based bulk amorphous
metal alloys have been previously described. For example, one
previously described class of ferrous-based bulk amorphous metal
alloys is a high manganese-high molybdenum class that contains
manganese, molybdenum, and carbon as the principal alloying
components. This class of Fe--Mn--Mo--Cr--C--(B) [element in
parenthesis is the minority constituent] amorphous alloys is known
as the DARPA Virginia-Glass1 (DARVA-Glass1). Another known class of
ferrous-based bulk amorphous metal alloys is a high-manganese class
that contains manganese and boron as the principal alloying
components. This class of Fe--Mn--(Cr,Mo)--(Zr,Nb)--B alloys is
known as the DARVA-Glass2. By incorporating phosphorus in
DARVA-Glass1, the latter is modified to form
Fe--Mn--Mo--Cr--C--(B)--P amorphous alloys known as DARVA-Glass102.
These bulk-solidifying amorphous alloys can be obtained in various
forms and shapes for various applications and utilizations.
However, it is anticipated that the glass formability properties as
well as other beneficial properties of such ferrous-based bulk
amorphous metal alloys can be improved by the addition of
large-atom elements in the alloy. More particularly, the improved
iron based bulk-solidifying amorphous alloys of the present
invention can be prepared from commercial grade material and
processed into cylinder samples having a diameter of 3, 4, 5, 6 or
7 millimeters or even greater.
In accordance with one embodiment of the present invention, an
iron-based amorphous alloy with enhanced glass formability
properties is provided wherein the alloy is represented by the
formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qM.sub.dX.sub.rZ.sub.sQ.sub.g
I wherein M represents one or more elements selected from the group
consisting of Al, Ga, In, Sn, Si, Ge and Sb;
X represents one or more elements selected from the group
consisting of Ti, Zr, Hf, Nb, V, W and Ta;
Z is an element selected from the group consisting of C, Co or
Ni;
Q represents one or more large-atom metals wherein the sum of the
atomic percentage of said large-atom metals is equal to g; n, m, p,
q, d, r, s and g are atomic percentages, wherein n is a number
selected from 0 to about 29; m and p are independently a number
selected from 0 to about 16, wherein n+m is at least 10; q is a
number selected from about 6 to about 21; r and d are independently
selected from 0 to about 4; s is a number selected from 0 to about
20; g is a number greater than 0 but less than or equal to about
10; and
t is the sum of n, m, p, q, r, s, d and g, with the proviso that t
is a number selected from about 40 to about 60. In accordance with
one embodiment, an alloy of the general formula I is provided
wherein M is an element selected from the group consisting of Al,
Ga, In, Sn, Si, Ge and Sb; X is an element selected from the group
consisting of Ti, Zr, Hf, Nb, V, W and Ta; Z is an element selected
from the group consisting of C, Co or Ni; and Q is an element
selected from the group consisting of Sc, Y, Ce, Pr, Nd, Pm, Sm,
Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. In accordance with another
embodiment an alloy of the general formula I is provided wherein Fe
content is at least about 45%, Z is carbon, s is about 13 to about
17, q is at least about 4, d and r are both 0, and the sum of m, p
and g is less than about 20. In a further embodiment, an alloy of
the general formula I is provided wherein Fe content is at least
about 45%, Z is carbon and s is about 13 to about 17, q is at least
about 4, d and r are both 0, the sum of m, p and g is less than
about 20 and Q is an element selected from the group consisting of
Sc, Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and
Lu.
In another embodiment the improved alloy of the present invention
is represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qC.sub.sQ.sub.g II
wherein Q is an element selected from the group consisting of Y,
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu,
n is a number selected from 0 to about 12,
m is a number selected from 0 to about 16, wherein n+m is at least
10,
p is a number selected from about 8 to about 16,
s is at least about 13;
q is at least about 5;
g is a number greater than 0 but less than or equal to about 3; and
t is the sum of n, m, p, q, s and g, with the proviso that the sum
of p and g is less than about 16, and t is not greater than about
55. In one embodiment t is a number selected from about 38 to about
55 and Q is an element selected from the group consisting of Sc, Y,
Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. In one embodiment an alloy of
general formula II is prepared wherein t is a number selected from
about 45 to about 55; Q is an element selected from the group
consisting of Sc, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu and the
alloy further comprises 2% or less of other refractory metals (Ti,
Zr, Hf, Nb, V, W and Ta) and 2% or less of "Group B" elements
selected from the group consisting of Al, Ga, In, Sn, Si, Ge and
Sb. In one embodiment an alloy of general formula II is prepared
using commercial grade materials and can be processed into cylinder
samples having a diameter of 5 millimeters or greater.
Moreover, in another embodiment, phosphorus is incorporated into
the MnMoC-alloys to modify the metalloid content, with the goal of
further enhancing the corrosion resistance. Various ranges of
thickness are possible. For example, in one embodiment,
bulk-solidified non-ferromagnetic amorphous samples of greater than
about 3 mm or 4 mm in diameter can be obtained. The phosphorus
containing alloys of the present invention are represented by the
formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qC.sub.sQ.sub.gP.sub.z
wherein Q is an element selected from the group consisting of Sc,
Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu,
n is a number selected from 0 to about 12,
m is a number selected from 0 to about 16, wherein n+m is at least
10,
p is a number selected from about 8 to about 16,
s is at least about 13;
q is at least about 5;
g is a number greater than 0 but less than or equal to about 3;
z is a number selected from about 5 to about 12; and t is the sum
of n, m, p, q, s, g and z, with the proviso that the sum of p and g
is less than 16, and t is not greater than 55. In one embodiment t
is a number selected from about 38 to about 55 and Q is an element
selected from the group consisting of Sc, Y, Gd, Tb, Dy, Ho, Er,
Tm, Yb and Lu.
In one embodiment the alloy is represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qC.sub.sQ.sub.g wherein
Q is an element selected from the group consisting of Sc, Y, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu;
n is a number selected from about 7 to about 12;
m is a number selected from about 4 to about 6;
p is a number selected from about 8 to about 15,
g is a number selected from about 1 to about 3, and p+g equals a
number selected from about 11 to about 15;
s+q equals at least 18; and
t is a number ranging from about 47 to about 53. In one embodiment,
Q is an element selected from the group consisting of Sc, Y, Ce,
Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. In another embodiment, the
alloy is represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qC.sub.sQ.sub.g wherein
Q is an element selected from the group consisting of Sc, Y, Gd,
Tb, Dy, Ho, Er, Tm, Yb and Lu;
n is a number selected from 0 to about 10;
m is a number selected from about 4 to about 16;
p is a number selected from about 8 to about 12,
g is a number selected from about 2 to about 3, and p+g equals a
number selected from about 11 to about 14;
s is a number selected from about 14 to about 16;
q is a number selected from about 5 to about 7; and
t is the sum of n, m, p, q, s and g, and is a number selected from
about 46 to about 54. 6 mm-diameter or larger amorphous rods are
obtained in the compositional domain using this alloy. Furthermore,
7 mm-diameter or larger amorphous rods are obtained in the
compositional domain using an alloy represented by the formula
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qC.sub.sQ.sub.g wherein
Q is an element selected from the group consisting of Sc, Y, Gd,
Tb, Dy, Ho, Er, Tm, Yb and Lu;
n is a number selected from 0 to about 2;
m is a number selected from about 11 to about 16;
p is a number selected from about 8 to about 12,
g is a number selected from about 2 to about 3, and p+g equals a
number selected from about 11 to about 14;
s is a number selected from about 14 to about 16;
q is a number selected from about 5 to about 7; and
t is the sum of n, m, p, q, s and g, and is a number selected from
about 47 to about 53. In one embodiment an alloy of formula II is
provided wherein Q is Y or Gd; n is about 5 to about 10; m is a
number selected from about 4 to about 6; g is a number selected
from about 2 to about 3, and p+g equals a number selected from
about 14 to about 15; s is a number selected from about 15 to about
16; q is about 6; and t is a number selected from about 47 to about
51. In a further embodiment, Q is Y or Gd; n is about 10; m is
about 4; g is about 2; p+g equals about 14; s is a number selected
from about 15 to about 16; q is about 6; and t is a number selected
from about 47 to about 51. In one embodiment an alloy of formula II
is provided wherein Q is an element selected from the group
consisting of Sc, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; n is about
5 to about 10; m is a number selected from about 4 to about 6; g is
a number selected from about 2 to about 3, and p+g equals a number
selected from about 14 to about 15; s is a number selected from
about 15 to about 16; q is about 6; and t is a number selected from
about 47 to about 51.
In another embodiment of the present invention the alloy is
represented by the formula:
Fe.sub.(100-t)Cr.sub.mMo.sub.pB.sub.qC.sub.sQ.sub.g III wherein Q
is an element selected from the group consisting of Sc, Y, Gd, Tb,
Dy, Ho, Er, Tm, Yb and Lu;
m is a number selected from about 10 to about 20;
p is a number selected from about 5 to about 20;
q is a number selected from about 5 to about 7;
s is a number selected from about 15 to about 16;
g is a number selected from about 1 to about 3; and
t is the sum of m, p, q, s and g, and is a number selected from
about 47 to about 55. In one embodiment an alloy of general formula
III is prepared wherein m is a number selected from about 12 to
about 16; p is a number selected from about 10 to about 16; q is a
number selected from about 5 to about 7; s is a number selected
from about 15 to about 16; g is a number selected from about 2 to
about 3; and t is a number selected from about 47 to about 55.
In accordance with one embodiment the improved alloy of the present
invention comprises an alloy represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mB.sub.qSi.sub.dX.sub.rQ.sub.gNi.sub.s
IV wherein X is an element selected from the group consisting of
Mo, Ta or Nb;
Q is an element selected from the group consisting of Sc, Y, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu;
n is a number selected from about 10 to about 29;
m is a number selected from 0 to about 4, wherein n+m is at least
15 but less than 30;
d and r are numbers independently selected from 0 to about 4;
q is a number selected from about 17 to about 21, wherein d+q is
less than or equal to 23;
g is a number selected from about 4 to about 8;
s is a number ranging from 0 to about 20; and
t is the sum of n, m, q, r, d, s and g, with the proviso that t is
a number ranging from about 35 to about 55. In a further embodiment
an alloy of general formula IV is prepared wherein Q is an element
selected from the group consisting of Sc, Y, Gd, Tb, Dy, Ho, Er,
Tm, Yb and Lu, n is a number selected from about 15 to about 29; m
is 0, q is a number selected from about 17 to about 21; d is a
number ranging from about 1 to about 2; r is a number selected from
about 2 to about 3; s is a number ranging from 0 to about 20; g is
a number selected from about 4 to about 8; and t is a number
selected from about 45 to about 55. In a further embodiment an
alloy of general formula IV is prepared wherein Q is an element
selected from the group consisting of Y, Gd, Tb, Dy, Ho, Er, Tm, Yb
and Lu, n is a number selected from about 15 to about 29; m and r
are both 0, q is a number selected from about 17 to about 21; d is
a number ranging from about 1 to about 2; s is a number ranging
from 0 to about 20; g is a number selected from about 4 to about 8;
and t is a number selected from about 45 to about 55. In a further
embodiment an alloy of general formula IV is prepared wherein Q is
an element selected from the group consisting of Sc, Y, Gd, Tb, Dy,
Ho, Er, Tm, Yb and Lu, n is a number selected from about 15 to
about 29; m, d and r are each 0, q is a number selected from about
17 to about 21; s is a number ranging from 0 to about 20; g is a
number selected from about 4 to about 8; and t is a number selected
from about 45 to about 55.
In another embodiment of the present invention, the improved alloy
has the general formula Fe.sub.(100-t)Mn.sub.nX.sub.rB.sub.qQ.sub.g
wherein X is an element selected from the group consisting of Mo,
Ta or Nb; Q is an element selected from the group consisting of Sc,
Y, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, n is a number selected from
about 15 to about 29; r is a number selected from about 2 to about
3; q is a number selected from about 17 to about 21; g is a number
selected from about 4 to about 8; and t is the sum of n, r, q and
g, and is a number selected from about 45 to about 55.
In another embodiment the improved alloy of the present invention
comprises an alloy represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mB.sub.qSi.sub.dMo.sub.r1Nb.sub.r2Ta.sub.r3N-
i.sub.sQ.sub.g V
wherein Q is an element selected from the group consisting of Sc,
Y, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu;
n is a number ranging from 15 to about 29;
m is a number ranging from 0 to about 4, wherein
n+m is at least 15;
q is a number ranging from about 17 to about 21;
r1, r2 and r3 are independently selected from 0 to about 4;
d is a number ranging from 0 to about 4;
s is a number ranging from 0 to about 20;
g is a number ranging from about 4 to about 8; and
t is the sum of n, m, q, r1, r2, r3, d, s and g, with the proviso
that t is a number ranging from about 40 to about 65. In a further
embodiment an alloy of general formula V is prepared wherein Q is
an element selected from the group consisting of Sc, Y, Gd, Tb, Dy,
Ho, Er, Tm, Yb and Lu, n is a number ranging from 15 to about 29, m
is a number ranging from 0 to about 4, wherein n+m is at least 15,
q is a number ranging from about 17 to about 21, r1, r2 and r3 are
independently selected from 0 to about 4, d is a number ranging
from 0 to about 4, s is 0, g is a number ranging from about 4 to
about 8, and t is a number ranging from about 45 to about 55.
Similar to previously disclosed amorphous steel alloys, the
addition of about 10 atomic percent or higher manganese and
chromium significantly suppresses the ferromagnetism. Only
spin-glass-like magnetic transitions at 20-30 K are observed in
magnetization measurements performed at 100 Oe applied field.
Compositions of the present invention reveal that DARVA-Glass101
(i.e. DARVA-Glass1 alloys modified to include large-atom metals),
which contain significantly higher molybdenum content than
conventional steel alloys, exhibit much of the superior mechanical
strengths and good corrosion resistance similar to
DARVA-Glass1.
Preliminary measurements in one embodiment of the present invention
show microhardness in the range of about 1200-1300 DPN and
1000-1100 DPN for Fe--Mn--Cr--Mo--(Y,Ln)-C--B and Fe--Mn--Y--Nb--B
alloys, respectively. Based on these microhardness values, tensile
fracture strengths of 3-4 GPa are estimated. The latter values are
much higher than those reported for high-strength steel alloys.
Also similar to previous amorphous steel alloys, the present
invention is expected to exhibit elastic moduli comparable to
super-austenitic steels, and good corrosion resistance properties
comparable to those observed in amorphous iron- and nickel-based
alloys. Preliminary measurements of elastic constants place the
Young's moduli at .about.180-210 GPa and bulk modulus at
.about.140-180 GPa for DARVA-Glass101, and corresponding moduli of
.about.190 GPa and .about.140 GPa for DARVA-Glass201 (i.e.
DARVA-Glass2 alloys modified to include large-atom metals).
Although improved glass formability is generally seen in adding
yittrium (Y) or lanthanides (Ln) to Glass1, the largest
improvements are found when Y or Ln elements from the latter half
of the lanthanide series are selected. One class of improved
iron-based amorphous alloys is a modified DARVA-Glass1 known as
DARVA-Glass101 [Fe--Mn--Cr--Mo--(Y,Ln)-C--(B) type] alloys, where
the Y or Ln content is preferably 3 atomic percents or less.
As-cast amorphous rods of up to 12 mm or larger can be obtained in
DARVA-Glass101. Another other class iron-based amorphous alloys is
a modified DARVA-Glass2 known as DARVA-Glass201
[Fe--Mn--(Y,Ln)-B--(Si) type] alloys, where the preferred combined
Y or Ln and Nb or Mo contents are less than 10 atomic percents.
Casted amorphous rods of up to 4 mm can be obtained in
DARVA-Glass201.
Owing to the high glass formability and wide supercooled liquid
region, the amorphous alloys of the present invention can be
prepared as various forms of amorphous alloy products, such as thin
ribbon samples by melt spinning, amorphous powders by atomization,
consolidated products, amorphous rods, thick layers by any type of
advanced spray forming or scanning-beam forming, plastic forming,
plastic forming, compaction, and sheets or plates by casting.
Besides conventional injection casting, casting methods such as die
casting, squeeze casting, and strip casting as well as other
state-of the-art casting techniques currently employed in research
labs and industries can also be utilized. Additionally, other
"weaker" elements such as Al, Ga, In, Sn, Si, Ge, Sb, etc. which do
not exhibit large negative heats of mixing with Fe, Cr, and Mo can
be introduced to enhance the fluidity and therefore the
processibility of the cast products. Furthermore, one can exploit
the highly deformable behavior of the alloys in the supercooled
liquid region to form desired shapes of amorphous or
amorphous-composite products.
The present alloys may be devitrified to form amorphous-crystalline
microstructures, or infiltrated with other ductile phases during
solidification or melting of the amorphous alloys in the
supercooled-liquid region, to form composite materials, which can
result in strong hard products with improved ductility for
structural applications. In accordance with one embodiment of the
invention, the alloys can be made to exhibit the formation of
microcrystalline .gamma.-Fe upon cooling at a rate somewhat slower
than the critical cooling rate for glass formation. In this case,
the alloy can solidify into a composite structure consisting of
ductile microcrystalline .gamma.-Fe precipitates embedded in an
amorphous matrix. In this way, high strength bulk microcrystalline
.gamma.-Fe composites materials can be produced and thus the range
of practical applications is extended. In accordance with one
embodiment, the volume fraction and size of the .gamma.-Fe
precipitates are influenced by the cooling rate and the amount of
Ti and Ta in the alloy. For any given alloy composition, both the
volume fraction and size of the quasi-crystalline precipitates
increase with decreasing cooling rates.
In accordance with one embodiment of the present invention, an
article of manufacture is provided wherein the article comprises an
iron-based amorphous alloy represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qM.sub.dX.sub.rZ.sub.sQ.sub.g
I wherein M represents one or more elements selected from the group
consisting of Al, Ga, In, Sn, Si, Ge and Sb;
X represents one or more elements selected from the group
consisting of Ti, Zr, Hf, Nb, V, W and Ta;
Z is an element selected from the group consisting of C Co or
Ni;
Q represents one or more large-atom metals wherein the sum of the
atomic percentage of said large-atom metals is equal to g;
n, m, p, q, d, r, s and g are atomic percentages, wherein
n is a number selected from 0 to 29;
m and p are independently a number selected from 0 to 16,
wherein n+m is at least 10;
q is a number selected from 4 to 21;
r and d are independently selected from 0 to 4;
s is a number selected from 0 to 20;
g is a number greater than 0 but less than or equal to 10; and
t is the sum of n, m, p, q, r, s, d and g, with the proviso that t
is a number selected from 40 to 60. In accordance with one
embodiment, the article of manufacture comprises an alloy of the
general formula I wherein M is an element selected from the group
consisting of Al, Ga, In, Sn, Si, Ge and Sb; X is an element
selected from the group consisting of Ti, Zr, Hf, Nb, V, W and Ta;
Z is an element selected from the group consisting of C, Co or Ni;
and Q is an element selected from the group consisting of Sc, Y,
Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. In
accordance with another embodiment, the article of manufacture
comprises an alloy of the general formula I wherein Fe content is
at least about 45%, Z is carbon, s is a number selected from 13 to
17, q is a number selected from 4 to 7, d and r are both 0, and the
sum of m, p and g is less than 20. In a further embodiment, the
article of manufacture comprises an alloy of the general formula I
wherein Fe content is at least about 45% to about 55%, Z is carbon,
Q is an element selected from the group consisting of Sc, Y, Gd,
Tb, Dy, Ho, Er, Tm, Yb and Lu, n is a number selected from 0 to
about 15, m is a number selected from 0 to about 16, wherein n+m is
at least 15 but less than 30, p is a number selected from about 8
to about 16, s is about 13 to about 17, q is at least about 4 to
about 7, d and r are both 0, g is a number selected from about 2 to
about 3, and t is a number selected from about 46 to about 54.
In accordance with another embodiment, an article of manufacture is
provided wherein the article comprises an iron-based amorphous
alloy represented by the formula:
Fe.sub.(100-t)Mn.sub.nX.sub.rB.sub.qQ.sub.g wherein X is an element
selected from the group consisting of Mo, Ta or Nb; Q is an element
selected from the group consisting of Sc, Y, Gd, Tb, Dy, Ho, Er,
Tm, Yb and Lu, n is a number selected from about 15 to about 29; r
is a number selected from 2 to 3; q is a number selected from 17 to
21; g is a number selected from 4 to 8; and t is the sum of n, r, q
and g, and is a number selected from 45 to 55.
The novel alloys of the present invention provide non-ferromagnetic
properties at ambient temperature as well as useful mechanical
attributes. For example, the present invention alloys exhibit
magnetic transition temperatures below ambient, mechanical
strengths and hardness superior to conventional steel alloys, and
good corrosion resistance. Further advantages of the present alloys
include specific strengths as high as, for example, 0.5 MPa/(Kg/m3)
(or greater), which are the highest among bulk metallic glasses.
Additionally the present alloys possess thermal stabilities that
are the highest among bulk metallic glasses. The present alloys
also have reduced chromium content compared to current candidate
Naval steels, for example and can be prepared at significantly
lower cost (for example, lower priced goods and manufacturing
costs) compared with current refractory bulk metallic glasses.
Accordingly, the amorphous steel alloys of the present invention
outperform current steel alloys in many application areas. Some
products and services of which the present invention can be
implemented include, but are not limited to 1) ship, submarine
(e.g., watercrafts), and vehicle (land-craft and aircraft) frames
and parts, 2) building structures, 3) armor penetrators, armor
penetrating projectiles or kinetic energy projectiles, 4)
protection armors, armor composites, or laminate armor, 5)
engineering, construction, and medical materials and tools and
devices, 6) corrosion and wear-resistant coatings, 7) cell phone
and personal digital assistant (PDA) casings, housings and
components, 8) electronics and computer casings, housings, and
components, 9) magnetic levitation rails and propulsion system, 10)
cable armor, 11) hybrid hull of ships, wherein "metallic" portions
of the hull could be replaced with steel having a hardened
non-magnetic coating according to the present invention, 12)
composite power shaft, 13) actuators and other utilization that
require the combination of specific properties realizable by the
present invention amorphous steel alloys.
EXAMPLES
Practice of various embodiments will be still more fully understood
from the following examples, which are presented herein for
illustration only and should not be construed as limiting the
invention in any way.
Example 1
Ingot Preparation
Alloy ingots are prepared by melting mixtures of commercial grade
elements (e.g. iron is at most 99.9% pure) in an arc furnace or
induction furnace. In order to produce homogeneous ingots of the
complex alloys that contained manganese, refractory metals, and
metals of large-atom elements such as yittrium and the lanthanides,
as well as the metalloids particularly carbon, it was found to be
advantageous to perform the alloying in two or more separate
stages. For alloys that contain iron, manganese, and boron as the
principal components, a mixture of all the elements except
manganese was first melted together in an arc furnace. The ingot
obtained was then combined with manganese and melted together to
form the final ingot. For stage 2 alloying, it was found preferable
to use clean manganese obtained by pre-melting manganese pieces in
an arc furnace.
In the case of alloys that contain iron, manganese, molybdenum, and
carbon as the principal components, iron granules, graphite powders
(about -200 mesh), molybdenum powders (about -200 to -375 mesh),
and the large-atom elements plus chromium, boron, and phosphorous
pieces were mixed well together and pressed into a disk or cylinder
or any given mass. Alternatively, small graphite pieces in the
place of graphite powders can also be used. The mass is melted in
an arc furnace or induction furnace to form an ingot. The ingot
obtained was then combined with manganese and melted together to
form the final ingot.
Ingots with further enhanced homogeneity can be achieved by forming
Mn--(Y or Lanthanide element) and FeB precursor ingots that were
then used in place of Mn and B. In another embodiment, boron is
alloyed with iron to form near-stochiometric FeB compound. The
remaining Fe is then alloyed with Mo, Cr, C, and Sc, Y/Lanthanide
element as well as the FeB precursor to form
Fe--Mo--Cr--(Y/Ln)-C--B. If needed, additional elements such as
other refractory metals (Ti, Zr, Hf, Nb, V, Ta, W), Group B
elements (Al, Ga, In, Sn, Si, Ge, Sb), Ni, and Co can also be
alloyed in at this stage. Should the alloy contain Mn, a final
alloying step is carried out to incorporate Mn in the final
product.
Glass Formability and Processibility
Regarding the glass formability and processibility,
bulk-solidifying samples can be obtained using a conventional
copper mold casting, for example, or other suitable methods. In one
instance, bulk solidification is achieved by injecting the melt
into a cylinder-shaped cavity inside a copper block. Alternatively,
suction casting can be employed to obtain bulk-solidifying
amorphous samples similar in size to the injection-cast samples.
The prepared samples were sectioned and metallographically
examined, using an optical microscope to explore the homogeneity
across the fractured surface. X-ray (CuK.alpha.) diffraction was
performed to examine the amorphicity of the inner parts of the
samples. Thermal transformation data were acquired using a
Differential Thermal Analyzer (DTA). The designed ferrous-based
alloys were found to exhibit a reduced glass temperature Trg in the
range of .about.0.58-0.60 and supercooled liquid region .DELTA.Tx
in the range of .about.30-50.degree. C.
In the instant exemplary embodiment, the present invention
amorphous steel alloys were cast into cylinder-shaped amorphous
rods with diameters reaching 12 mm, or larger. Various ranges of
thickness, size, length, and volume are possible. For example, in
some embodiments the present invention alloys are processable into
bulk amorphous samples with a range thickness of about 0.1 mm or
greater. The amorphous nature of the rods is confirmed by x-ray and
electron diffraction as well as thermal analysis (FIGS. 1 to 3 and
5 show some of the results).
Example 2
Preparation of DARVA-Glass101 and DARVA-Glass201 Amorphous Steel
Alloys
Two classes of the non-ferromagnetic ferrous-based bulk amorphous
metal alloys of the present invention have been prepared. The
alloys in the subject two classes contain about 50 atomic % of iron
and are obtained by alloying two types of alloys with large-atom
elements. The first type (MnCrMoQC-amorphous steel alloy or
DARVA-Glass101) contains manganese, molybdenum, and carbon as the
principal alloying components, wherein Q symbolizes the large-atom
elements. The second type (MnQB-amorphous steel alloy or
DARVA-Glass201) contains manganese and boron as the principal
alloying components, wherein Q symbolizes the large-atom elements.
For illustration purposes, more than sixty compositions of each of
the two classes are selected for characterizing glass
formability.
First, regarding the DARVA-Glass101 MnCrMoLgC-amorphous steel
alloys, these alloys are given by the formula (in atomic percent)
as follows:
Fe.sub.100-a-b-c-d-eMn.sub.aCr.sub.bMo.sub.cQ.sub.d(C,B).sub.e
wherein Q=Y and Lanthanide elements, and 12.gtoreq.a.gtoreq.0,
16.gtoreq.b.gtoreq.0, 16.gtoreq.c.gtoreq.8, 3.gtoreq.d.gtoreq.0,
e.gtoreq.18, and under the following constraints that the sum of c
and d is less than 16, Fe content is at least about 45, C content
is at least about 13%, and B content is at least about 5% in the
overall alloy composition.
These alloys are found to exhibit a glass temperature Tg of
530-550.degree. C. (or greater), T.sub.rg of 0.58-0.60 (or greater)
and supercooled liquid region .DELTA.T.sub.x of 30-50.degree. C.
(or greater). DTA scans obtained for typical samples are shown in
FIGS. 2A and 2B. These alloys can be processed into shapes over a
selected range of thickness. For example, in some embodiments the
present invention alloys are processible into bulk amorphous
samples with a range thickness of at least 0.1 mm or greater.
Meanwhile the compositional range expressed in the above formula
can yield sample thickness of at least 1 mm or greater. In an
embodiment, the MnCrMoLgC-alloys can be readily cast into about 12
mm-diameter or larger rods. A camera photo of injection-cast
amorphous rods is displayed in FIG. 3.
Alloys that contain Y and the heavier Ln (from Gd to Lu), which can
form glassy samples with diameter thicknesses of 6-12 mm or larger,
are found to exhibit significantly higher glass formability than
those containing the lighter Ln (i.e. from Ce to Eu). For example,
the Mn-rich Glass101 alloys can only form 2 to 3 mm-diameter glassy
rods and the Cr-rich Glass101 can only form 2 to 6 mm-diameter
glassy rods when they are alloyed with the lighter Ln. For the Y
and heavier Ln bearing alloys, a maximum diameter thickness of up
to 7-10 mm can still be attained if 2 at. % or less of other
refractory metals (Ti, Zr, Hf, Nb, V, Ta, W) and Group B elements
(Al, Ga, In, Sn, Si, Ge, Sb) are also added. As mentioned above,
some of the latter additions are introduced to enhance the
processibility of the present amorphous steel alloys.
Because of the moderately high viscosity, the melt must be heated
to .about.150.degree. C. above T.sub.l in order to provide the
fluidity needed in copper mode casting. As a result, the
effectiveness in heat removal is compromised, which could limit the
diameter of the amorphous rods in this embodiment. Upon additional
alloying, thicker samples could also be achieved. The full
potential of these alloys as processible amorphous steel alloys can
be further exploited by employing more advanced casting techniques
such as high-pressure squeeze casting. Continuous casting methods
can also be utilized to produce sheets and strips. A variety of
embodiments representing a number of typical amorphous steel alloys
of the MnCrMoLgC class with C content of 15% and B content of 6%
together with the typical diameter of the bulk-solidifying
amorphous cylinder-shaped samples obtained and transformation
temperatures are listed in Table 1. At present, it is found in one
embodiment that alloys containing as low as about 19% combined (C,
B) metalloid content can be bulk solidified into about 6
mm-diameter amorphous rods. These exemplary embodiments are set
forth for the purpose of illustration only and are not intended in
any way to limit the practice of the invention.
TABLE-US-00001 TABLE 1 Thermal data obtained from differential
thermal analysis (DTA) scans of typical DARVA-Glass101
MnCrMoLgC-type amorphous steel alloys. Listed in the right-hand
column are amorphous rod diameter size, liquidus onset tempertature
T.sub.l.sup.onset, and peak temperature T.sub.l.sup.peak (or final
peak temperature T.sub.l.sup.peak/f for non-eutectic melting) in
the liquids region. The size of the supercooled liquid region is
about 30-50.degree. C., and T.sub.rg is 0.58-0.60. Results from
DARVA-Glass1 that do not contain the large-atom metals are included
for comparison. Fe.sub.51Mn.sub.10Mo.sub.14Cr.sub.4C.sub.15B.sub.6
4 mm; T.sub.g = 540.degree. C.; T.sub.l.sup.onset = 1080.degree.
C.; T.sub.l.sup.peak = 1115.degree. C.
Fe.sub.50Mn.sub.10Cr.sub.4Mo.sub.14Y.sub.1C.sub.15B.sub.6 4 mm;
T.sub.g = 550.degree. C.; T.sub.l.sup.onset = 1080.degree. C.; 3
T.sub.l.sup.peak = 1110.degree. C.
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.12Y.sub.2C.sub.15B.sub.6 7 mm;
T.sub.g = 530.degree. C.; T.sub.l.sup.onset = 1070.degree. C.;
T.sub.l.sup.peak = 1090.degree. C.
Fe.sub.52Mn.sub.10Cr.sub.4Mo.sub.12Yb.sub.1C.sub.15B.sub.6 4 mm;
T.sub.g = 540.degree. C.; T.sub.l.sup.onset = 1085.degree. C.;
T.sub.l.sup.peak = 1110.degree. C.
Fe.sub.53Mn.sub.10Cr.sub.4Mo.sub.10Yb.sub.2C.sub.15B.sub.6 6 mm;
T.sub.g = 540.degree. C.; T.sub.l.sup.onset = 1085.degree. C.;
T.sub.l.sup.peak = 1110.degree. C.
Fe.sub.49Mn.sub.10Cr.sub.8Mo.sub.10Yb.sub.2C.sub.15B.sub.6 6 mm;
T.sub.g = 550.degree. C.; T.sub.l.sup.onset = 1090.degree. C.;
T.sub.l.sup.peak = 1130.degree. C.
Fe.sub.51Mn.sub.10Cr.sub.10Mo.sub.10Yb.sub.2C.sub.15B.sub.6 6 mm;
T.sub.g = 558.degree. C.; T.sub.l.sup.onset = 1090.degree. C.;
T.sub.l.sup.peak = 1120.degree. C.
Fe.sub.54Mn.sub.10Cr.sub.4Mo.sub.8Yb.sub.3C.sub.15B.sub.6 4 mm;
T.sub.g = 523.degree. C.; T.sub.l.sup.onset = 1085.degree. C.;
T.sub.l.sup.peak = 1115.degree. C.
Fe.sub.49Mn.sub.10Cr.sub.4Mo.sub.14Yb.sub.2C.sub.15B.sub.6 4 mm;
T.sub.g = 540.degree. C.; T.sub.l.sup.onset = 1078.degree. C.;
T.sub.l.sup.peak = 1100.degree. C.
Fe.sub.53Mn.sub.10Mo.sub.14Yb.sub.2C.sub.15B.sub.6 4 mm; T.sub.g =
540.degree. C.; T.sub.l.sup.onset = 1060.degree. C.;
T.sub.l.sup.peak = 1085.degree. C.
Fe.sub.49Mn.sub.10Cr.sub.8Mo.sub.10Yb.sub.2C.sub.15B.sub.6 5 mm;
T.sub.g = 550.degree. C.; T.sub.l.sup.onset = 1090.degree. C.;
T.sub.l.sup.peak = 1130.degree. C.
Fe.sub.50Mn.sub.7Cr.sub.10Mo.sub.10Yb.sub.2C.sub.15B.sub.6 5 mm;
T.sub.g = 558.degree. C.; T.sub.l.sup.onset = 1090.degree. C.;
T.sub.l.sup.peak = 1120.degree. C.
Fe.sub.50Mn.sub.10Cr.sub.4Mo.sub.12Yb.sub.3C.sub.15B.sub.6 6 mm;
T.sub.g = 530.degree. C.; T.sub.l.sup.onset = 1070.degree. C.;
T.sub.l.sup.peak = 1110.degree. C.
Fe.sub.53Mn.sub.10Cr.sub.4Mo.sub.10Gd.sub.2C.sub.15B.sub.6 5 mm;
T.sub.g is not clear; T.sub.l.sup.onset = 1080.degree. C.;
T.sub.l.sup.peak = 1100.degree. C.
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.12Gd.sub.2C.sub.15B.sub.6 6 mm;
T.sub.g is not clear; T.sub.l.sup.onset = 1080.degree. C.;
T.sub.l.sup.peak = 1100.degree. C.
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.12Dy.sub.2C.sub.15B.sub.6 7 mm;
T.sub.g = 530.degree. C.; T.sub.l.sup.onset = 1065.degree. C.;
T.sub.l.sup.peak = 1110.degree. C.
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.12Er.sub.2C.sub.15B.sub.6 7 mm;
T.sub.g = 540.degree. C.; T.sub.l.sup.onset = 1070.degree. C.;
T.sub.l.sup.peak = 1110.degree. C.
Fe.sub.50Mn.sub.9Cr.sub.4Mo.sub.14Er.sub.2C.sub.15B.sub.6 6 mm;
T.sub.g = 535.degree. C.; T.sub.l.sup.onset = 1070.degree. C.;
T.sub.l.sup.peak = 1095.degree. C.
Fe.sub.50Mn.sub.10Cr.sub.4Mo.sub.12Er.sub.3C.sub.15B.sub.6 6 mm;
T.sub.g = 530.degree. C.; T.sub.l.sup.onset = 1075.degree. C.;
T.sub.l.sup.peak = 1100.degree. C.
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.12Tm.sub.2C.sub.15B.sub.6 7 mm;
T.sub.g = 530.degree. C.; T.sub.l.sup.onset = 1070.degree. C.;
T.sub.l.sup.peak = 1105.degree. C.
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.12Tb.sub.2C.sub.15B.sub.6 6 mm;
T.sub.g = 530.degree. C.; T.sub.l.sup.onset = 1060.degree. C.;
T.sub.l.sup.peak = 1100.degree. C.
Fe.sub.48Cr.sub.13Mn.sub.2Mo.sub.14Er.sub.2C.sub.15B.sub.6 7 mm;
T.sub.g = 575.degree. C.; T.sub.l.sup.onset = 1105.degree. C.;
T.sub.l.sup.peak/f = 1170.degree. C.
Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 12-13 mm; Tg =
570.degree. C.; T.sub.l.sup.onset = 1100.degree. C.;
T.sub.l.sup.peak/f = 1160.degree. C.
Fe.sub.50Cr.sub.15Mo.sub.12Er.sub.2C.sub.15B.sub.6 8 mm; Tg =
565.degree. C.; T.sub.l.sup.onset = 1105.degree. C.;
T.sub.l.sup.peak/f = 1160.degree. C.
Fe.sub.52Cr.sub.15Mo.sub.9Er.sub.3C.sub.15B.sub.6 6 mm; T.sub.g =
535.degree. C.; T.sub.l.sup.onset = 1105.degree. C.;
T.sub.l.sup.peak/f = 1170.degree. C.
Fe.sub.48Cr.sub.15Mo.sub.14Dy.sub.2C.sub.15B.sub.6 11 mm; T.sub.g =
570.degree. C.; T.sub.l.sup.onset = 1105.degree. C.;
T.sub.l.sup.peak/f = 1165.degree. C.
Fe.sub.48Cr.sub.15Mo.sub.14Y.sub.2C.sub.15B.sub.6 10 mm; T.sub.g =
570.degree. C.; T.sub.l.sup.onset = 1105.degree. C.;
T.sub.l.sup.peak/f = 1170.degree. C.
Fe.sub.48Cr.sub.15Mo.sub.14Lu.sub.2C.sub.15B.sub.6 11 mm; T.sub.g =
570.degree. C.; T.sub.l.sup.onset = 1105.degree. C.;
T.sub.l.sup.peak/f = 1170.degree. C.
For alloys with 14.5-16% C and 6.5-6.0% B, and which also contain
the heavier lanthanide elements, the effects on sample size due to
large atom additions are summarized as follows:
Fe.sub.100-a-b-c-d-eMn.sub.aCr.sub.bMo.sub.cQ.sub.d(C,B).sub.e
4 mm-diameter or larger amorphous rods are obtained in the
compositional domain wherein 12.gtoreq.a.gtoreq.0,
16.gtoreq.b.gtoreq.0, 16.gtoreq.c+d.gtoreq.11, 3.gtoreq.d.gtoreq.1,
55>a+b+c+d+e>45; 6 mm-diameter or larger amorphous samples
are obtained in the compositional domain wherein10.gtoreq.a0,
16.gtoreq.b.gtoreq.4, 14.gtoreq.c+d.gtoreq.11, 3.gtoreq.d.gtoreq.2,
54>a+b+c+d+e>46; and 7 mm-diameter or larger amorphous
samples are obtained in the compositional domain wherein
2.gtoreq.a.gtoreq.0, 16.gtoreq.b.gtoreq.11,
14.gtoreq.c+d.gtoreq.11, 3.gtoreq.d.gtoreq.2,
53>a+b+c+d+e>47.
The maximum attainable thicknesses for Cr-rich Glass101, when
alloyed with the lighter lanthanide elements, are 1.5 mm, 2.5 mm, 3
mm, 5 mm, and 6 mm for La, Nd, Eu, Ce, and Sm, respectively. Much
of the latter results can be explained by noting that the actual
amounts of lanthanide detected in these lighter lanthanide bearing
alloys are significantly lower than the nominal lanthanide contents
originally added. Apparently, the majority of the lanthanide
contents form volatile oxides that evaporate from the melt.
Several features are noted in the investigated DARVA-Glass101 alloy
series. Both T.sub.l.sup.onset & T.sub.l.sup.peak are seen to
increase slightly with Cr content. T.sub.l.sup.onset is seen to
decrease slightly with 2-3 at. % of lanthanide additions.
Meanwhile, T.sub.g also rises with increasing Cr content, as
illustrated in Table 1. The optimal contents of Y and the
lanthanides for forming large size rods are at 2 to 3 at. %.
Finally, the as-cast rod diameters of some of the alloys listed in
Table 1 do not necessarily represent the maximum size attainable.
This is because for these alloys, larger size rods have not been
cast.
Based on DTA measurements and devitrification studies, a plausible
mechanism of high glass formability in DARVA-Glass101 is proposed.
From Table 1, it is demonstrated that the significant improvement
in the glass formability upon adding the large-atom metals to
DARVA-Glass1 to form DARVA-Glass101 is evidently not attributable
to the T.sub.g or T.sub.rg values observed. This is because the
change in T.sub.g is not systematic upon adding large-atom metals
to the high-Mn alloys, and T.sub.rg remains at 0.6. As for the
high-Cr alloys, T.sub.rg is even lower at 0.58. Meanwhile,
devitrification studies have provided some clues for understanding
the enhanced glass formability. DARVA-glass101 is seen to exhibit a
higher stability against crystallization than Glass1, as can be
seen in FIG. 4. Comparing with DARVA-Glass1, the crystallization of
101 in forming the Cr.sub.23C.sub.6-phase (cF116 structure) is much
delayed upon annealing both Glasses near the onset of their similar
crystallization temperatures T.sub.x. The more sluggish
crystallization kinetics of Glass 101 may be attributed to the fact
that the large-atom metals that are encaged inside the amorphous
structure must be rejected from the glass during the nucleation and
growth of the Cr.sub.23C.sub.6-phase. If confirmed, the latter
scenario would lend evidence to the mechanism of enhanced glass
formability from the melt via destabilization of the crystalline
phase.
Regarding the DARVA-Glass201 MnLgB-amorphous steel alloys, these
alloys are given by the formula (in atomic percent) as follows:
Fe.sub.100-a-b-c-d-e(Mn,
Cr).sub.a(Nb,Ta,Mo).sub.bQ.sub.cB.sub.dSi.sub.e wherein Q=Sc, Y and
elements from the lanthanide series, and 29.gtoreq.a.gtoreq.10,
4.gtoreq.b.gtoreq.0, 8.gtoreq.c.gtoreq.4, 21.gtoreq.d.gtoreq.17,
4.gtoreq.e.gtoreq.0, with the proviso that the sum of d and e is no
more than 23, Fe content is at least about 45, Mn content is at
least 10, and Cr content is less than 4. The alloy composition can
further be modified by substituting up to 20% Fe with Ni.
These alloys are found to exhibit a glass temperature T.sub.g of
about 520-600.degree. C. (or greater), T.sub.rg .about.0.58-0.61
(or greater) and supercooled liquid region .DELTA.T.sub.x of about
40-60.degree. C. (or greater). DTA scans obtained from typical
samples are shown in FIGS. 5A and 5B. These alloys can be processed
into shapes over a selected range of thickness. For example, in
some embodiments the present invention alloys are processable into
bulk amorphous samples with a range thickness of at least 0.1 mm or
greater. The compositional range expressed in the above formula can
yield a sample thickness of at least 1 mm or greater. In one
embodiment, the MnLgB alloys can be readily cast into amorphous
rods of diameter of 4 mm.
The full potential of these alloys as processible amorphous steel
alloys can be further exploited by employing more advanced casting
techniques such as high-pressure squeeze casting. Continuous
casting methods can also be utilized to produce sheets and strips.
A variety of embodiments representing a number of typical amorphous
steel alloys of the MnLgB class together with the typical diameter
of the bulk-solidifying amorphous cylinder-shaped samples obtained
and transformation temperatures are listed in Table 2A. Table 2B
lists additional representative alloys and the typical sample sizes
attainable. These exemplary embodiments are set forth for the
purpose of illustration only and are not intended in any way to
limit the practice of the invention.
TABLE-US-00002 TABLE 2A Transformation temperatures of typical
DARVA-Glass201 MnLgB-class amorphous steel alloys and diameter of
bulk-solidifying cylinder-shaped amorphous samples obtained.
T.sub.g T.sub.x T.sub.l Amorphous Rod Alloy Composition (.degree.
C.) (.degree. C.) (.degree. C.) Diameter (mm)
Fe.sub.62Mn.sub.18B.sub.20 -- 470 1180 --
Fe.sub.55Mn.sub.18Y.sub.10B.sub.17 -- 680 1100 --
Fe.sub.59Mn.sub.18Y.sub.3B.sub.20 520 560 1130 --
Fe.sub.57Mn.sub.18Y.sub.5B.sub.20 560 610 1130 2.0
Fe.sub.55Mn.sub.18Y.sub.7B.sub.20 -- 665 1120 1.0
Fe.sub.55Mn.sub.18Nb.sub.2Y.sub.5B.sub.20 580 630 1120 3.5
Fe.sub.54Mn.sub.18Nb.sub.2Y.sub.6B.sub.20 590 650 1120 3.0
Fe.sub.48Mn.sub.25Nb.sub.2Y.sub.5B.sub.20 575 630 1110 3.0
Fe.sub.50Mn.sub.23Nb.sub.2Y.sub.5B.sub.20 580 640 1110 4.0
Fe.sub.50Mn.sub.23Mo.sub.2Y.sub.5B.sub.20 570 625 1180 3.0
Fe.sub.48Mn.sub.23Nb.sub.2Y.sub.5B.sub.20Si.sub.2 600 660 1150 3.5
Fe.sub.40Ni.sub.18Mn.sub.15Nb.sub.2Y.sub.5B.sub.20 550 593 1180
1.5
TABLE-US-00003 TABLE 2A Additional DARVA-Glass201 alloyse
cross-sectional size of amorphous samples. Amorphous Rod Diameter
Alloy Composition (mm) Fe.sub.59Mn.sub.18Y.sub.5B.sub.18 1.0
Fe.sub.54Mn.sub.18Y.sub.8B.sub.20 1.0
Fe.sub.56Mn.sub.18Y.sub.4Er.sub.2B.sub.20 2.0
Fe.sub.54Mn.sub.18Nb.sub.3Y.sub.5B.sub.20 1.5
Fe.sub.53Mn.sub.18Nb.sub.3Y.sub.6B.sub.20 1.5
Fe.sub.54Mn.sub.18Nb.sub.2Y.sub.5B.sub.20Si.sub.1 3.5
Fe.sub.50Mn.sub.23Ta.sub.2Y.sub.5B.sub.20 2.0
Fe.sub.50Mn.sub.23Nb.sub.2Gd.sub.5B.sub.20 3.0
Fe.sub.48.5Mn.sub.21Cr.sub.2Nb.sub.2Y.sub.5B.sub.20Si.sub.1.5
3.5
Example 3
Some aspects of the various embodiments provide a bulk-solidifying
high manganese non-ferromagnetic amorphous steel alloys and related
method of using and making articles (e.g., systems, structures,
components, coatings, etc.) of the same. One class is a high
manganese-high molybdenum class that contains manganese,
molybdenum, and carbon as the principal alloying components. This
class of Fe--Mn--Mo--Cr--C--(B) [element in parenthesis is the
minority constituent] amorphous alloys are currently known as DARPA
Virginia-Glass1 (aka DARVA-Glass1). Another class is a
high-manganese class that contains manganese and boron as the
principal alloying components. This class of
Fe--Mn--(Cr--Mo--(Zr,Nb)--B alloys is known as DARVA-Glass2. By
incorporating phosphorus in DARVA-Glass1, the latter is modified to
form Fe--Mn--Mo--Cr--C--(B)--P amorphous alloys known as
DARVA-Glass102. These bulk-solidifying amorphous alloys can be
obtained in various forms and shapes for various applications and
utilizations. The largest diameter size of amorphous cylinder
samples obtained reaches 4 millimeters. Still further, another
aspect provides a highly formable non-ferromagnetic amorphous steel
alloys obtained by using large-size atom additions and related
method of using and making the same. The addition of large atoms,
Y, Er and other lanthanides greatly increases the size of the
cylindrical bulk glass diameters that are obtainable, i.e, improves
the glass formability. This class of
Fe--Mn--Cr--Mo--(Y,lanthanide)-C--B alloys are known as DARVA101.
The good processability of these alloys can be attributed to the
high reduced glass temperature T.sub.rg (e.g., about 0.6 to 0.63)
and large supercooled liquid region .DELTA.T.sub.x (e.g., about
50-100.degree. C.). On aspect is to utilize these amorphous steels
as coatings, rather than strictly bulk structural applications. In
this fashion any structural metal alloy can be coated by various
technologies by these alloys for protection from the environment.
Although results for only several candidate alloys are presented in
this disclosure, all chemistry ranges listed in prior disclosures
concerning DARVA amorphous steel alloys are claimed.
Similarly, various aspects provide a new approach for significantly
improving the corrosion and wear resistance of metallic-based
coatings. The products that result from the present invention
approach provides a novel series of non-ferromagnetic amorphous
alloys at ambient temperature and related method of using and
making articles (e.g., systems, structures, components) of the
same. The unique chemistries involved in producing the amorphous
alloy coatings are disclosed herein. Conventional methods can be
employed to apply the coating to a substrate or the like. The
unique compositions readily form bulk glasses so coatings that are
amorphous can be readily achieved. Regarding the glass formability
and processability, the amorphous nature of the alloy is confirmed
by x-ray and electron diffraction as well as thermal analysis, as
shown in FIG. 6. Owing to the high glass formability and wide
supercooled liquid region, the invention DARVA-Glasses can be
produced into various forms of amorphous alloy products, such as
thin ribbon samples by melt spinning, amorphous powders by
atomization, consolidated products, amorphous rods, thick layers by
any type of advanced spray forming for coatings. Accordingly, the
aspects of the various embodiments of the present invention of
amorphous steel coatings outperform current steel alloys without
coatings in many application areas that require corrosion, wear and
erosion protection. Some products and services of which the present
invention can be implemented includes, but is not limited thereto
1) ship, submarine (e.g., watercrafts), and vehicle (land-craft and
aircraft) frames and parts, 2) building structures, 3) armor
penetrators, armor penetrating projectiles or kinetic energy
projectiles, 4) protection armors, armor composites, or laminate
armor, 5) engineering, construction, and medical materials and
tools and devices, 6) corrosion and wear-resistant coatings, 7)
cell phone and personal digital assistant (PDA) casings, housings
and components, 8) electronics and computer casings, housings, and
components, 9) magnetic levitation rails and propulsion system, 10)
cable armor, 11) hybrid hull of ships, wherein "metallic" portions
of the hull could be replaced with steel having a hardened
non-magnetic coating according to the present invention, 12)
composite power shaft, 13) actuators and other utilization that
require the combination of specific properties realizable by the
present invention amorphous steel alloys.
Example 4
Corrosion Tests Of Amorphous Steel Alloys
1. Test Conditions:
(a) Sample Preparation Method
Bulk rods were sealed in EPO-THIN low viscosity epoxy
(resin+hardener). Nickel wire was pasted on one end of the rod
using silver adhesive serving as electric connection. The cross
section of rod was first ground using SiC paper discs up to US grit
size 1200, then polished using Al.sub.2O.sub.3 or diamond
suspensions down to 0.05 .mu.m particle size. After each test, the
cross section was reground and repolished so that the influence of
the previous test can be ignored in the following corrosion
test.
Optical Microscopy was used for examining and comparing the cross
sections of rods before/after tests.
(b) Experiment Types and Parameters
Corrosion tests have been performed in three representative
solutions with different pH values, i.e., pH=6.5 (.about.neutral),
pH=1.0 (acid), and pH=11.0 (base). Appropriate amount of NaCl was
added in solutions to produce a same Cl.sup.- concentration of 0.6
M (0.6 Molar/Liter). In each solution, typical tests performed for
each sample included: open circuit test (OCP), linear polarization
(LP), and cyclic polarization (CP). Nitrogen was used to drive away
oxygen in solution for at least one hour before tests, and this
deaeration process also remained on during the test. Important
experiment parameters were kept same or close for reasonable
comparison. For each composition, multiple tests were performed for
each pH value and each test type to obtain reliable data, See Table
3. For those rods with irregular cross section, the accuracy of the
measured sample area is restricted, but the results are
repeatable.
TABLE-US-00004 TABLE 3 Number of different types of corrosion tests
(OCP, LP, CP) performed in different solutions (pH = 1, 6.5, 11).
ID Fe03-2/ Fe03-507 Fe03-400 Fe03-284 Fe03-630 Fe04-084 Fe04-631 pH
OCP LP CP OCP LP CP OCP LP CP OCP LP CP OCP LP CP OCP LP CP 1 5 1 5
2 2 2 2 2 2 4 4 4 1 1 1 2 2 2 6.5 3 1 3 3 1 3 2 2 2 4 4 4 2 2 2 2 2
2 11 4 4 4 4 4 4 1 1 1 1 1 1 3 3 3 2 2 2 Notes: Fe03507:
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6 Fe03284:
Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 Fe04084:
Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6
Method Introduction (a) From Open Circuit Potential (OCP)
measurement, we obtain open circuit potential in different
solutions. (b) From Linear Sweep (Linear Polarization over small
voltage range, typically 20 mV below OCP to OCP), we can obtain
polarization resistance R.sub.p. (c) From Cyclic Polarization
tests, we can obtain pitting potential E.sub.pit, repassivation
potential E.sub.repass, Tafel slopes (.beta..sub.a, .beta..sub.c)
E.sub.corr and i.sub.corr. Data analyses are by (1). Tafel Fitting,
which may not be suitable for cases where obvious anodic
passivation occurs since this method is assumed to be hold only in
active region (activation polarization) of both cathodic and anodic
polarizations. (2) In cases where no obvious pitting and
repassivation processes occur, we define the pitting and
repassivation potentials at a certain current density (for example,
10.sup.-4 A/cm.sup.2, depending on the alloys). Otherwise we obtain
the pitting and repassivation potentials from the straight-forward
positions (where dE/di.about.0). (d) We define
B=(.beta.a.beta.c)/(2.3(.beta.a+.beta.c)), and the i.sub.corr
should be able to calculated according to the following
equation:
.times. ##EQU00001## Special attention should be paid to the units
of different parameters. Ideally, this calculated i.sub.corr should
be close to the one obtained from Tafel fitting, given that the
polarizations are suitable for Tafel fitting (active region, see
above). But significant deviation could appear if the polarization
process shows obvious passivation stage (in this case, doing Tafel
fitting itself is questionable). (e) From this calculated
i.sub.corr we can estimate the corrosion rate (typically .mu.m/year
is used for all alloys in this disclosure). During the calculation,
only ionization of Fe occurs. The problem becomes very complicate
if we consider all elements such as Mn, Mo, Cr, C and B, etc. This
simplification would not influence the magnitude significantly
since Fe dominates in all compositions and other elements are less
active than Fe. (f) Typically, we may mostly be interested in the
following important parameters: corrosion rate (reflected by
i.sub.corr, the smaller the better), pitting potential (the higher
the better), the difference between the pitting potential and the
open circuit potential E.sub.oc (the larger the better). And, it's
certainly helpful to know the pH dependence of the above parameters
under current Cl.sup.- concentration. Corrosion Rate Evaluation
Method Used in this Disclosure:
Consider a major oxidation (anodic) reaction,
A.fwdarw.A.sup.n++ne.sup.-; We have,
.times..rho..times..times. ##EQU00002## where I is the current, d
the corrosion depth, S.sub.0 the cross section area, .rho. the
density of metal A, M the molar mass of metal A, n is the number of
electrons lost in the major anodic reaction, N.sub.o the Avogadro
constant, e the charge of an electron, t the time. And we have
N.sub.oe=F (Faraday constant, 96487 Coulomb/mole). Define average
corrosion rate as .chi.=d/t, then
.chi..times..times..rho..times..times. ##EQU00003## where
i=I/S.sub.0 is the current density in unit of A/cm.sup.2, which is
calculated using parameters extracted from Tafel Fit (CP tests) and
Rp Fit (LP tests). Using density in unit of g/cm.sup.3, we will
have corrosion rate in unit of cm/sec, which can be converted to
other units such as .mu.m/year. For alloys, simplifications are
required to get the corrosion rate. The simplest one is assuming
only the dominating element is dissolved. 1. Corrosion Results
(a) Fe03507: Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6
Referring to FIG. 7, FIG. 7 graphically provides Open Circuit
Potential (OCP) and Linear Sweep Polarization (LP) for alloy
Fe.sub.51Mn.sub.10 Cr.sub.4Mo.sub.14C.sub.15B.sub.6. It should be
noted the large fluctuation of potential during linear polarization
(LP) tests is an indicator of "passivation," which is consistent
with CP tests, i.e., in acid solution, the chance of passivation
for this alloy is less.
Referring to FIG. 8, FIG. 8 graphically provides cyclic potential
(CP) results for alloy
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6 in basic,
neutral and acidic solutions. The corrosion behavior changes with
pH value systematically. In acid solution (dashed-line curve),
passivation and pitting are the least obvious. In base solution
(thin-line curve), passivation (and repassivation) and pitting are
very obvious. In neutral solution (dark-line curve), things are
somewhere in between the two extremes. (See Data comparison shown
in Table 4).
Optical Microscopy:
FIG. 9 provides depictions of optical microscope images of sample
surface for alloy
Fe.sub.51Mn.sub.10Cr.sub.4Mo.sub.14C.sub.15B.sub.6 in basic,
neutral and acidic solutions following CP tests. The FIG. 9 photos
are taken after pH=1, after pH=11, before pH6.5 and after pH=6.5 CP
tests, clockwise from upper left. Notes: After CP test in acid
solution, a thin brown layer formed on the surface, together with a
few pits. This layer can be wiped off. After CP test in base
solution, almost no changes on the sample surface can be observed
under optical microscopy, except at a few places along the
sample-resin interface (edge), "crystal-like" particles can be
seen. After CP test in pH=6.5 NaCl solution, the surface is similar
as the one after test in acid solution, except that the number of
pits and the corrosion layer are much less.
What described above regarding FIG. 9 is universal for alloys with
similar compositions. The surface changes before/after CP tests are
consistent with what we have seen in CP curves. For example, due to
the passivation in base solution, the surface has less change,
while in acid solution, the continuously increased current may
produce the brown layer (e.g., Fe(OH).sub.2).
(b) Fe03284: Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6
FIG. 10 provides a graphical Open Circuit Potential (OCP) and
Linear Sweep Polarization (LP) for alloy
Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6. Similarly as
Fe03507, the passivation tendency increases with the increasing pH
value, and the open circuit potential decreases with the increasing
pH values.
FIG. 11 provides a graphical Cyclic potential (CP) results for
alloy Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 in basic,
neutral and acidic solutions. The changing tendency of CP curves
with pH values is similar as Fe03507. But the current density is
smaller in this case (comparing x-axis). This reflects smaller
corrosion rate, due to the increased Cr amount, see Data comparison
shown in Table 4.
FIG. 12 depicts optical microscope images of sample surface for
alloy Fe.sub.48Cr.sub.15Mo.sub.14Er.sub.2C.sub.15B.sub.6 before and
after CP at pH 6.5. The relation between the degree of surface
changes and pH values is similar as Fe03507. For example, very
limited amount of pits appear. Sample edge may show features like
crystalline particles. This big rod (4 mm) has a couple of
intrinsic holes, which cannot be removed by grinding/polishing.
Because of the small corrosion current (resulted from high Cr
amount), no surface corrosion layer (the color of this layer
depends on the corrosion product of different Fe-compounds) was
seen even after CP tests in acid solution.
(c) Fe04084: Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6
FIG. 13 provides a graphical Open Circuit Potential (OCP) and
Linear Sweep Polarization (LP) for alloy
Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6. Similarly, the
passivation tendency increases with the increasing pH value. But
the open circuit potential-pH relation is not the same as Fe03507
and Fe03284.
FIG. 14 provides a graphical Cyclic potential (CP) results for
alloy Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6 in basic, neutral
and acidic solutions.
FIG. 15 depicts Optical microscope images of sample surface for
alloy Fe.sub.50Cr.sub.15Mo.sub.14C.sub.15B.sub.6 before and after
CP at pH 6.5. Surface change is also not large. Limited amount of
pits and layer appear, particularly near edge.
FIG. 16 graphically provides pitting potential and the difference
between pitting potential and open circuit potential vs pH for the
three different amorphous steels discussed in this disclosure. Also
compared with some common metal elements.
Provided is the pitting potential and the difference between
pitting potential and open circuit potential vs pH for different
materials. It can be noted that the larger these quantities, the
more difficult for this material to corrode under the similar
environments.
Next, in can be noted that corrosion rate of Fe-based alloys
decreases with increasing pH value of solution (under current
Cl.sup.- concentration). The accuracy of the data is expected
within {0.1.times.corrosion_rate, 10.times.corrosion_rate}, for
example, if a corrosion rate of 1 .mu.m/y is shown, it could vary
between 0.1 to 10 .mu.m/y, which is the best estimate using current
method. As discussed in the method introduction part, Tafel fitting
can not be very suitable when passivation-like behavior appears
during anodic polarization. Also because of this problem, the
corrosion rates of pure elements shown below are less accurate. So,
data of pure elements are only given for future evaluation of the
validity of current analysis method.
Comparing Fe03507 with Fe03284, the data are reasonable. Increasing
Cr atomic ratio improves the corrosion resistance. Comparing
Fe04084 and Fe03284, 2% substitution of Fe by Er significantly
improve the corrosion resistance.
FIG. 17 provides a bar graph illustrating the loss of material per
year because of corrosion for a variety of elements at various pH
levels.
TABLE-US-00005 E.sub.oc E.sub.corr i.sub.corr E.sub.pit
E.sub.repass E.sub.pit-E.sub.oc- .chi. Sample ID pH (V) (V)
(nA/cm.sup.2) (V) (V) (V) (.mu.m/year) Fe03507:
Fe51Mn10Cr4Mo14C15B6* 1.0 -0.262 -0.325 594 -0.06 0.09 0.202 6.89-
6.5 -0.442 -0.563 335 0.34 0.19 0.782 3.89 11.0 -0.503 -0.645 350
0.76 0.43 1.263 1.26 Fe03284: Fe48Cr15Mo14Er2C15B6** 1.0 -0.130
-0.339 63 0.58 N/A 0.710 0.73 6.5 -0.243 -0.264 70 0.64 N/A 0.883
0.81 11.0 -0.359 -0.391 55 0.77 N/A 1.129 0.64 Fe04084:
Fe50Cr15Mo14C15B6*** 1.0 -0.237 -0.356 2554 -0.15 N/A 0.087 29.62-
6.5 -0.444 -0.698 977 -0.20 N/A 0.244 11.33 11.0 -0.327 -0.562 170
0.45 N/A 0.777 1.97 *For pH = 11, pitting and repassivation are
well defined. For pH = 6.5, pitting defined; repassivation is
assumed at 1E-4A/cm.sup.2. For pH = 1, pitting and repassivation
are assumed at 5.4E-6 A/cm.sup.2; repassivation is assumed at 1E-4
A/cm.sup.2 **For pH = 1, pitting is assumed at 5.4E-6 A/cm.sup.2;
no obvious repassivation for all solutions. Instead, almost
overlapped at reverse point (hysterias loop is small or ~zero)
***For pH = 1, define pitting at 5.4E-6 A/cm.sup.2; no obvious
pitting for acid solution; no obvious re-passivation for all
solutions.
The various embodiments of the present invention material,
structures, method of using and fabrication may be implemented with
the embodiments disclosed in the following Patents, patent
applications, references and publications as listed below and are
hereby incorporated by reference herein in their entirety:
U.S. Pat. No. 4,676,168 to Cotton et al. entitled "Magnetic
Assemblies for Minesweeping or Ship Degaussing;"
U.S. Pat. No. 5,820,963 to Lu et al. entitled "Method of
Manufacturing a Thin Film Magnetic Recording Medium having Low MrT
Value and High Coercivity;"
U.S. Pat. No. 5,866,254 to Peker et al. entitled "Amorphous
metal/reinforcement Composite Material;"
U.S. Pat. No. 6,446,558 to Peker et al. entitled "Shaped-Charge
Projectile having an Amorphous-Matrix Composite Shaped-charge
Filter;"
U.S. Pat. No. 5,896,642 to Peker et al. entitled "Die-formed
Amorphous Metallic Articles and their Fabrication;"
U.S. Pat. No. 5,797,443 to Lin, Johnson, and Peker entitled "Method
of Casting Articles of a Bulk-Solidifying Amorphous Alloy;"
U.S. Pat. No. 4,061,815 to Poole entitled "Novel Compositions;"
U.S. Pat. No. 4,353,305 to Moreau, et al. entitled "Kinetic-energy
Projectile;"
U.S. Pat. No. 5,228,349 to Gee et al. entitled "Composite Power
Shaft with Intrinsic Parameter Measurability;"
U.S. Pat. No. 5,728,968 to Buzzett et al. entitled "Armor
Penetrating Projectile;"
U.S. Pat. No. 5,732,771 to Moore entitled "Protective Sheath for
Protecting and Separating a Plurality for Insulated Cable
Conductors for an Underground Well;" and
U.S. Pat. No. 5,868,077 to Kuznetsov entitled "Method and Apparatus
for Use of Alternating Current in Primary Suspension Magnets for
Electrodynamic Guidance with Superconducting Fields;"
U.S. Pat. No. 6,357,332 to Vecchio entitled "Process for Making
Metallic/intermetallic Composite Laminate Material and Materials so
Produced Especially for Use in Lightweight Armor;"
U.S. Pat. No. 6,505,571 to Critchfield et al. entitled "Hybrid Hull
Construction for Marine Vessels;"
U.S. Pat. No. 6,515,382 to Ullakko entitled "Actuators and
Apparatus;"
TABLE-US-00006 U.S. Pat. No. 5,738,733 Inoue A. et al. U.S. Pat.
No. 5,961,745 Inoue A. et al. U.S. Pat. No. 5,976,274 Inoue A. et
al. U.S. Pat. No. 6,172,589 Fujita K. et al. U.S. Pat. No.
6,280,536 Inoue A. et al. U.S. Pat. No. 6,284,061 Inoue A. et al.
U.S. Pat. No. 5,626,691 Li, Poon, and Shiflet U.S. Pat. No.
6,057,766 O'Handley et al.
U.S. patent application Publication No. US 2005/0034792 A1 (Ser.
No. 10/639,277) to Lu et al.
U.S. patent application Publication No. US 2004/00154701 A1 (Ser.
No. 10/364,988) to Lu et al.
"Synthesis and Properties of Ferromagnetic Bulk Amorphous Alloys",
A. Inoue, T. Zhang, H. Yoshiba, and T. Itoi, in Bulk Metallic
Glasses, edited by W. L. Johnson et al., Materials Research Society
Proceedings, Vol. 554, (MRS Warrendale, Pa., 1999), p. 251.
"The Formation and Functional Properties of Fe-Based Bulk Glassy
Alloys", A. Inoue, A. Takeuchi, and B. Shen, Materials
Transactions, JIM, Vol. 42, (2001), p. 970.
"New Fe--Cr--Mo--(Nb,Ta)--C--B Alloys with High Glass Forming
Ability and Good Corrosion Resistance", S. Pang, T. Zhang, K.
Asami, and A. Inoue, Materials Transactions, JIM, Vol. 42, (2001),
p. 376.
"(Fe, Co)--(Hf, Nb)--B Glassy Thick Sheet Alloys Prepared by a Melt
Clamp Forging Method", H. Fukumura, A. Inoue, H. Koshiba, and T.
Mizushima, Materials Transactions, JIM, Vol. 42, (2001), p.
1820.
"Universal Criterion for Metallic Glass Formation", T. Egami,
Mater. Sci. Eng. A Vol. 226-228, (1997), p. 261.
"Synthesis of iron-based bulk metallic glasses as nonferromagnetic
amorphous steel alloys", V. Ponnambalam, S. J. Poon, G. J. Shiflet,
V. M. Keppens, R. Taylor, and G. Petculescu, Appl. Phys. Lett. Vol.
83, (2003), p. 1131.
Still other embodiments will become readily apparent to those
skilled in this art from reading the above-recited detailed
description and drawings of certain exemplary embodiments. It
should be understood that numerous variations, modifications, and
additional embodiments are possible, and accordingly, all such
variations, modifications, and embodiments are to be regarded as
being within the spirit and scope of this application. For example,
regardless of the content of any portion (e.g., title, field,
background, summary, abstract, drawing figure, etc.) of this
application, unless clearly specified to the contrary, there is no
requirement for the inclusion in any claim herein or of any
application claiming priority hereto of any particular described or
illustrated activity or element, any particular sequence of such
activities, or any particular interrelationship of such elements.
Moreover, any activity can be repeated, any activity can be
performed by multiple entities, and/or any element can be
duplicated. Further, any activity or element can be excluded, the
sequence of activities can vary, and/or the interrelationship of
elements can vary. Unless clearly specified to the contrary, there
is no requirement for any particular described or illustrated
activity or element, any particular sequence or such activities,
any particular size, speed, material, dimension or frequency, or
any particularly interrelationship of such elements. Accordingly,
the descriptions and drawings are to be regarded as illustrative in
nature, and not as restrictive. Moreover, when any number or range
is described herein, unless clearly stated otherwise, that number
or range is approximate. When any range is described herein, unless
clearly stated otherwise, that range includes all values therein
and all sub ranges therein. Any information in any material (e.g.,
a United States/foreign patent, United States/foreign patent
application, book, article, etc.) that has been incorporated by
reference herein, is only incorporated by reference to the extent
that no conflict exists between such information and the other
statements and drawings set forth herein. In the event of such
conflict, including a conflict that would render invalid any claim
herein or seeking priority hereto, then any such conflicting
information in such incorporated by reference material is
specifically not incorporated by reference herein.
* * * * *