U.S. patent application number 12/265982 was filed with the patent office on 2011-01-06 for non-ferromagnetic amorphous steel alloys containing large-atom metals.
Invention is credited to Vijayabarathi Ponnambalam, S. Joseph Poon, Gary J. Shiflet.
Application Number | 20110000585 12/265982 |
Document ID | / |
Family ID | 34279765 |
Filed Date | 2011-01-06 |
United States Patent
Application |
20110000585 |
Kind Code |
A1 |
Poon; S. Joseph ; et
al. |
January 6, 2011 |
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 Se, 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.
Inventors: |
Poon; S. Joseph;
(Charlottesville, VA) ; Ponnambalam; Vijayabarathi;
(Clemson, SC) ; Shiflet; Gary J.;
(Charlottesville, VA) |
Correspondence
Address: |
UNIVERSITY OF VIRGINIA PATENT FOUNDATION
250 WEST MAIN STREET, SUITE 300
CHARLOTTESVILLE
VA
22902
US
|
Family ID: |
34279765 |
Appl. No.: |
12/265982 |
Filed: |
November 6, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10559002 |
Nov 30, 2005 |
7517415 |
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PCT/US04/16442 |
May 25, 2004 |
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12265982 |
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60475185 |
Jun 2, 2003 |
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60513612 |
Oct 23, 2003 |
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60546761 |
Feb 23, 2004 |
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Current U.S.
Class: |
148/403 ; 164/46;
164/57.1; 75/338; 75/571 |
Current CPC
Class: |
C22C 45/00 20130101;
C22C 45/02 20130101; C22C 33/003 20130101 |
Class at
Publication: |
148/403 ; 75/571;
164/46; 164/57.1; 75/338 |
International
Class: |
C22C 45/02 20060101
C22C045/02; C22B 9/00 20060101 C22B009/00; B22D 23/00 20060101
B22D023/00; B22D 27/00 20060101 B22D027/00; B22F 9/06 20060101
B22F009/06 |
Goverment Interests
US Government Rights
[0002] This invention was made with United States Government
support under ONR Grant No. N00014-01-10961 awarded by the Defense
Advance Research Projects Agency/Office of Naval Research. The
United States Government has certain rights in the invention.
Claims
1. An 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
wherein 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; 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; M is an element selected from the group consisting
of Al, Ga, In, Sn, Si, Ge and Sb; 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.
2. The alloy of claim 1, wherein Q is an element selected from the
group consisting of Sc, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
3. 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.
4. The alloy of claim 1 or 2 wherein 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
n is a number selected from 0 to about 29; m is a number selected
from 0 to about 16, wherein n+m is at least 15; p is a number
selected from 0 to about 16; q is a number selected from about 4 to
about 8; s is about 13 to about 17; g is a number greater than 0
but less than or equal to about 3; and t is a number selected from
about 40 to about 55.
5. The alloy of claim 4 wherein 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 14, p is a number selected from about 8 to about 16, q is
a number selected from about 4 to about 8; s is about 13 to about
17; g is a number selected from about 1 to about 3; and t is a
number selected from about 45 to about 55.
6. The alloy of claim 2 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 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, q is at least about 5; r is a number
selected from greater than 0 to about 2; d is 0; s is at least
about 13; g is a number selected from about 1 to about 3; and t is
a number selected from about 38 to about 55.
7. The alloy of claim 2 wherein 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, q is
at least about 5; d is a number selected from greater than 0 to
about 2; r is 0; s is at least about 13; g is a number selected
from about 1 to about 3; and t is a number selected from about 38
to about 55.
8. The alloy of claim 1 or 2 wherein the alloy is represented by
the formula: Fe.sub.(100-t)Cr.sub.mMo.sub.pB.sub.qC.sub.sQ.sub.g 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.
9. The alloy of claim 1 or 2 wherein the alloy is represented by
the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qSi.sub.dX.sub.rNi.-
sub.sQ.sub.g wherein X is Ta or Nb; 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; p, 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, d, r, s
and g, with the proviso that t is a number ranging from about 35 to
about 55.
10. The alloy of claim 9 wherein the alloy is represented by the
formula: Fe.sub.(100-t)Mn.sub.nB.sub.qSi.sub.dX.sub.rQ.sub.g
wherein X is Ta or Nb; n is a number selected from about 15 to
about 29; q is a number selected from about 17 to about 21; d is a
number ranging from 0 to about 2; r is a number selected from about
2 to about 3; g is a number selected from about 4 to about 8; and t
is a number selected from about 45 to about 55.
11. The alloy of claim 10 wherein d and r are both 0.
12. An iron-based amorphous alloy represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mB.sub.qSi.sub.d
Mo.sub.r1Nb.sub.r2Ta.sub.r3Ni.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 15 to about 29; m is a number selected from 0 to about 4,
wherein n+m is at least 15; q is a number selected from about 17 to
about 21; d is a number selected from 0 to about 4; r1, r2 and r3
are numbers independently selected from 0 to about 4; s is a number
selected from 0 to about 20; g is a number selected 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 selected from about 40 to about
65.
13. The alloy of claim12 wherein Q is an element selected from the
group consisting of Sc, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.
14.-16. (canceled)
17. An alloy comprising 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.su-
b.sQ.sub.g 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; in 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.
18. The alloy of claim 17 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 carbon or Co; 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; 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.
19. The alloy of claim 17 wherein 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 45 to about 55.
20. The alloy of claim 17 wherein the article of manufacture
comprises an iron-based amorphous alloy represented by the formula:
Fe.sub.(100-t)Mn.sub.nX.sub.rB.sub.gQ.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.
21. A method of preparing homogeneous ingots of an iron-based
amorphous alloy comprising large-atom metals, manganese and boron,
said method comprising the steps of forming an FeB precursor ingot;
forming a Mn-large-atom metal precursor ingot; melting and mixing
the FeB precursor ingot with the remaining elements of the alloy,
but excluding the Mn-large-atom metal precursor ingot, to form an
alloy mixture; combining said alloy mixture with the manganese
Mn-large-atom metal precursor ingot; and melting the combination
together to form a homogenous ingot.
22. The method of claim 21 wherein said manganese is pre-melted in
an arc furnace to provide a clean source of manganese prior to
combining the manganese with the large-atom metal to form the
Mn-large-atom metal precursor ingot.
23. The method of claim 21 or 22 wherein boron is alloyed with iron
to form near-stochiometric FeB precursor ingot, with the remaining
Fe being alloyed with the remaining elements of the alloy prior to
said combining step.
24. 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.
25. 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.
26. 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.
27. 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.
28. 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.
29. 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.
30. 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.
31. The alloy of claim 1, wherein said alloy is processable into an
article.
32. The alloy of claim 31, 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, compaction and commercially available
manufacturing methods.
33. The alloy of claim 1, wherein said alloy is processable into a
coating.
34. The alloy of claim 33, 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, compaction and commercially available
coating methods
35. The alloy of claim 1, wherein said coating comprises corrosion
resistant type coating and/or wear-resistant type coating.
36. The alloy of claim 33, wherein said coating is disposed on a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane frames, ship parts,
submarine parts, vehicle parts, airplane parts, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, engineering and medical materials and
tools, cell phone and PDA casings, housings, and components,
electronics and computer casings, housings and components.
37. 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, airplane frames, ship parts,
submarine parts, vehicle parts, airplane parts, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, engineering and medical materials and
tools, cell phone and PDA casings, housings, and components,
electronics and computer casings, housings and components.
38. The alloy of claim 12, wherein said alloy is processable into
bulk amorphous samples of less than about 0.1 mm in thickness in
its minimum dimension.
39. The alloy of claim 12, wherein said alloy is processable into
bulk amorphous samples of at least about 0.1 mm in thickness in its
minimum dimension.
40. The alloy of claim 12, wherein said alloy is processable into
bulk amorphous samples of at least about 0.5 mm in thickness in its
minimum dimension.
41. The alloy of claim 12, wherein said alloy is processable into
bulk amorphous samples of at least about 1 mm in thickness in its
minimum dimension.
42. The alloy of claim 12, wherein said alloy is processable into
bulk amorphous samples of at least about 5 mm in thickness in its
minimum dimension.
43. The alloy of claim 12, wherein said alloy is processable into
bulk amorphous samples of at least about 10 mm in thickness in its
minimum dimension.
44. The alloy of claim 12, wherein said alloy is processable into
bulk amorphous samples of at least about 12 mm in thickness in its
minimum dimension.
45. The alloy of claim 12, wherein said alloy is processable into
an article.
46. The alloy of claim 45, 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, compaction, and commercially available
manufacturing methods.
47. The alloy of claim 12, wherein said alloy is processable into a
coating.
48. The alloy of claim 47, 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, compaction, and commercially available
coating methods
49. The alloy of claim 47, wherein said coating comprises corrosion
resistant type coating and/or wear-resistant type coating.
50. The alloy of claim 47, wherein said coating is disposed on a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane frames, ship parts,
submarine parts, vehicle parts, airplane parts, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, engineering and medical materials and
tools, cell phone and PDA casings, housings, and components,
electronics and computer casings, housings and components.
51. The alloy of claim 12, wherein said alloy is processable into a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane frames, ship parts,
submarine parts, vehicle parts, airplane parts, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, engineering and medical materials and
tools, cell phone and PDA casings, housings, and components,
electronics and computer casings, housings and components.
52.-65. (canceled)
66. The alloy of claim 17, wherein said alloy is processable into
bulk amorphous samples of less than about 0.1 mm in thickness in
its minimum dimension.
67. The alloy of claim 17, wherein said alloy is processable into
bulk amorphous samples of at least about 0.1 mm in thickness in its
minimum dimension.
68. The alloy of claim 17, wherein said alloy is processable into
bulk amorphous samples of at least about 0.5 mm in thickness in its
minimum dimension.
69. The alloy of claim 17, wherein said alloy is processable into
bulk amorphous samples of at least about 1 mm in thickness in its
minimum dimension.
70. The alloy of claim 17, wherein said alloy is processable into
bulk amorphous samples of at least about 5 mm in thickness in its
minimum dimension.
71. The alloy of claim 17, wherein said alloy is processable into
bulk amorphous samples of at least about 10 mm in thickness in its
minimum dimension.
72. The alloy of claim 17, wherein said alloy is processable into
bulk amorphous samples of at least about 12 mm in thickness in its
minimum dimension.
73. The alloy of claim 17, wherein said alloy is processable into
an article.
74. The alloy of claim 73, 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, compaction, and commercially available
manufacturing methods.
75. The alloy of claim 17, wherein said alloy is processable into a
coating.
76. The alloy of claim 75, 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, compaction, and commercially available
coating methods
77. The alloy of claim 75, wherein said coating comprises corrosion
resistant type coating and/or wear-resistant type coating.
78. The alloy of claim 75, wherein said coating is disposed on a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane frames, ship parts,
submarine parts, vehicle parts, airplane parts, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, engineering and medical materials and
tools, cell phone and PDA casings, housings, and components,
electronics and computer casings, housings and components.
79. The alloy of claim 17, wherein said alloy is processable into a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane frames, ship parts,
submarine parts, vehicle parts, airplane parts, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, engineering and medical materials and
tools, cell phone and PDA casings, housings, and components,
electronics and computer casings, housings and components.
80. The method of claim 21, further comprising processing said
alloy into bulk amorphous samples of less than about 0.1 mm in
thickness in its minimum dimension.
81. The method of claim 21, further comprising processing said
alloy into bulk amorphous samples of at least about 0.1 mm in
thickness in its minimum dimension.
82. The method of claim 21, further comprising processing said
alloy into bulk amorphous samples of at least about 0 5 mm in
thickness in its minimum dimension.
83. The method of claim 21, further comprising processing said
alloy into bulk amorphous samples of at least about 1 mm in
thickness in its minimum dimension.
84. The method of claim 21, further comprising processing said
alloy into bulk amorphous samples of at least about 5 mm in
thickness in its minimum dimension.
85. The method of claim 21, further comprising processing said
alloy into bulk amorphous samples of at least about 10 mm in
thickness in its minimum dimension.
86. The method of claim 21, further comprising processing said
alloy into bulk amorphous samples of at least about 12 mm in
thickness in its minimum dimension.
87. The method of claim 21, further comprising processing said
alloy into an article.
88. The method of claim 87, wherein said processed article is
provided by at least one of the following processing methods: melt
spinning, atomization, spray forming, scanning-beam foaming,
plastic forming, casting, compaction and commercially available
manufacturing methods.
89. The method of claim 21, further comprising processing said
alloy into a coating.
90. The method of claim 89, 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, compaction, and commercially available
coating methods
91. The method of claim 89, wherein said coating comprises
corrosion resistant type coating and/or wear-resistant type
coating.
92. The method of claim 89, wherein said coating is disposed on a
structure selected from the group consisting of ship frames,
submarine frames, vehicle frames, airplane frames, ship parts,
submarine parts, vehicle parts, airplane parts, armor penetrators,
projectiles, protection armors, rods, train rails, cable armor,
power shaft, and actuators, engineering and medical materials and
tools, cell phone and PDA casings, housings, and components,
electronics and computer casings, housings and components.
93. The method of claim 21, further comprising processing said
alloy into a structure selected from the group consisting of ship
frames, submarine frames, vehicle frames, airplane parts, ship
parts, submarine parts, vehicle parts, airplane parts, armor
penetrators, projectiles, protection armors, rods, train rails,
cable armor, power shaft, and actuators, engineering and medical
materials and tools, cell phone and PDA casings, housings, and
components, electronics and computer casings, housings and
components.
94. An amorphous steel alloy having the composition:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMo.sub.pB.sub.qC.sub.sY.sub.g, where
n is from about 7 to about 12, m is from about 4 to about 6, p is
from about 8 to about 15, g is from about 1 to about 3, p+g equals
from about 11 to about 15, s+q equals at least 18, and t is from
about 47 to about 53.
95. An amorphous steel alloy having the composition:
Fe.sub.50Mn.sub.10Cr.sub.4Mo.sub.14Y.sub.1C.sub.15B.sub.6.
Description
RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
application Ser. No. 10/559,002, filed Nov. 30, 2005, 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, the disclosures of which are
incorporated herein by reference.
BACKGROUND
[0003] 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.
[0004] 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, (the disclosures of which are hereby incorporated
by reference). 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.
[0005] 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.1.3 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
[0006] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] 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-Glass101).
[0008] 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.
[0009] 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.
[0010] 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.
[0011] FIGS. 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.
DETAILED DESCRIPTION OF EMBODIMENTS
DEFINITIONS
[0012] In describing and claiming the invention, the following
terminology will be used in accordance with the definitions set
forth below.
[0013] As used herein, the term "reduced glass temperature (Trg)"
is defined as the glass transition temperature (Tg) divided by the
liquidus temperature (T1) in K.
[0014] As used herein, the term "large supercooled liquid region
(.DELTA.Tx)" is defined as crystallization temperature minus the
glass transition temperature.
[0015] As used herein, the term "large-atom metals" refers to
elements having an atom size ratio of approximately 1.3 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.
[0016] 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.
[0017] 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
[0018] 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.
[0019] 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.
[0020] 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.
[0021] 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.
[0022] 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;
[0023] X represents one or more elements selected from the group
consisting of Ti, Zr, Hf, Nb, V, W and Ta;
[0024] Z is an element selected from the group consisting of C, Co
or Ni;
[0025] Q represents one or more large-atom metals wherein the sum
of the atomic percentage of said large-atom metals is equal to
g;
[0026] n, m, p, q, d, r, s and g are atomic percentages, wherein
[0027] n is a number selected from 0 to about 29; [0028] m and p
are independently a number selected from 0 to about 16, wherein n+m
is at least 10; [0029] q is a number selected from about 6 to about
21; [0030] r and d are independently selected from 0 to about 4;
[0031] s is a number selected from 0 to about 20; [0032] g is a
number greater than 0 but less than or equal to about 10; and
[0033] 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.
[0034] In another embodiment the improved alloy of the present
invention is represented by the formula:
Fe.sub.(100-t)Mn.sub.nCr.sub.mMn.sub.pB.sub.qC.sub.sQ.sub.g II
[0035] 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,
[0036] n is a number selected from 0 to about 12,
[0037] m is a number selected from 0 to about 16, wherein n+m is at
least 10,
[0038] p is a number selected from about 8 to about 16,
[0039] s is at least about 13;
[0040] q is at least about 5;
[0041] 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.
[0042] 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,
[0043] n is a number selected from 0 to about 12,
[0044] m is a number selected from 0 to about 16, wherein n+m is at
least 10,
[0045] p is a number selected from about 8 to about 16,
[0046] s is at least about 13;
[0047] q is at least about 5;
[0048] g is a number greater than 0 but less than or equal to about
3;
[0049] 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.
[0050] 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;
[0051] n is a number selected from about 7 to about 12;
[0052] m is a number selected from about 4 to about 6;
[0053] p is a number selected from about 8 to about 15,
[0054] g is a number selected from about 1 to about 3, and p+g
equals a number selected from about 11 to about 15;
[0055] s+q equals at least 18; and
[0056] 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.mMn.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;
[0057] n is a number selected from 0 to about 10;
[0058] m is a number selected from about 4 to about 16;
[0059] p is a number selected from about 8 to about 12,
[0060] g is a number selected from about 2 to about 3, and p+g
equals a number selected from about 11 to about 14;
[0061] s is a number selected from about 14 to about 16;
[0062] q is a number selected from about 5 to about 7; and
[0063] 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;
[0064] n is a number selected from 0 to about 2;
[0065] m is a number selected from about 11 to about 16;
[0066] p is a number selected from about 8 to about 12,
[0067] g is a number selected from about 2 to about 3, and p+g
equals a number selected from about 11 to about 14;
[0068] s is a number selected from about 14 to about 16;
[0069] q is a number selected from about 5 to about 7; and
[0070] 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.
[0071] 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;
[0072] m is a number selected from about 10 to about 20;
[0073] p is a number selected from about 5 to about 20;
[0074] q is a number selected from about 5 to about 7;
[0075] s is a number selected from about 15 to about 16;
[0076] g is a number selected from about 1 to about 3; and
[0077] 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.
[0078] 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;
[0079] 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;
[0080] n is a number selected from about 10 to about 29;
[0081] m is a number selected from 0 to about 4, wherein n+m is at
least 15 but less than 30;
[0082] d and r are numbers independently selected from 0 to about
4;
[0083] q is a number selected from about 17 to about 21, wherein
d+q is less than or equal to 23;
[0084] g is a number selected from about 4 to about 8;
[0085] s is a number ranging from 0 to about 20; and
[0086] 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.
[0087] 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.
[0088] 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.d
Mo.sub.r1Nb.sub.r2Ta.sub.r3Ni.sub.sQ.sub.g V
[0089] 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;
[0090] n is a number ranging from 15 to about 29;
[0091] m is a number ranging from 0 to about 4, wherein [0092] n+m
is at least 15;
[0093] q is a number ranging from about 17 to about 21;
[0094] r1, r2 and r3 are independently selected from 0 to about
4;
[0095] d is a number ranging from 0 to about 4;
[0096] s is a number ranging from 0 to about 20;
[0097] g is a number ranging from about 4 to about 8; and
[0098] 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.
[0099] 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.
[0100] 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).
[0101] Although improved glass formability is generally seen in
adding yittrium (Y) or lanthanides (Ln) to Glassl, 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-Glass 1 known as
DARVA-Glass 101 [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.
[0102] 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, 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.
[0103] 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.
[0104] 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.mMn.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;
[0105] X represents one or more elements selected from the group
consisting of Ti, Zr, Hf, Nb, V, W and Ta;
[0106] Z is an element selected from the group consisting of C Co
or Ni;
[0107] Q represents one or more large-atom metals wherein the sum
of the atomic percentage of said large-atom metals is equal to
g;
[0108] n, m, p, q, d, r, s and g are atomic percentages, wherein
[0109] n is a number selected from 0 to 29; [0110] m and p are
independently a number selected from 0 to 16,
[0111] wherein n+m is at least 10; [0112] q is a number selected
from 4 to 21; [0113] r and d are independently selected from 0 to
4; [0114] s is a number selected from 0 to 20; [0115] g is a number
greater than 0 but less than or equal to 10; and
[0116] 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.
[0117] 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.
[0118] 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.
[0119] 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.
Example 1
Ingot Preparation
[0120] 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.
[0121] 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.
[0122] 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
[0123] 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.
[0124] 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
[0125] 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.
[0126] First, regarding the DARVA-Glass 101 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,
c.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.
[0127] These alloys are found to exhibit a glass temperature
T.sub.g 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.
[0128] 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.
[0129] 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.
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.;
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. Listed in the right-hand
column are amorphous rod diameter size, liquidus onset temperature
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 liquidus 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.
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.sup.cQ.sub.d(C,B).sub.e
[0130] 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 wherein
10.gtoreq.a.gtoreq.0, 16.gtoreq.b.gtoreq.4, 14c+d11,
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.
[0131] 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.
[0132] 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.
[0133] Based on DTA measurements and devitrification studies, a
plausible mechanism of high glass formability in DARVA-Glass 101 is
proposed. From Table 1, it is demonstrated that the significant
improvement in the glass formability upon adding the large-atom
metals to DARVA-Glassl 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
Glassl, 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 Glass101 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.
[0134] 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.
[0135] 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.
[0136] 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.513.sub.20 550 593 1180
1.5
TABLE-US-00003 TABLE 2A Additional DARVA-Glass201 alloyse
cross-sectional size of amorphous samples. Amorphous Rod Alloy
Composition Diameter (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
[0137] 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:
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entitled "Bulk-solidifying High Manganese Non-ferromagnetic
Amorphous Steel Alloys and Related Method of Using and Making the
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* * * * *