U.S. patent application number 15/916046 was filed with the patent office on 2019-07-18 for bulk nickel-niobium-phosphorus-boron glasses bearing low fractions of chromium and exhibiting high toughness.
The applicant listed for this patent is Glassimetal Technology, Inc.. Invention is credited to Marios D. Demetriou, Kyung-Hee Han, William L. Johnson, Maximilien Launey, Jong Hyun Na.
Application Number | 20190218649 15/916046 |
Document ID | / |
Family ID | 63446168 |
Filed Date | 2019-07-18 |
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United States Patent
Application |
20190218649 |
Kind Code |
A9 |
Na; Jong Hyun ; et
al. |
July 18, 2019 |
BULK NICKEL-NIOBIUM-PHOSPHORUS-BORON GLASSES BEARING LOW FRACTIONS
OF CHROMIUM AND EXHIBITING HIGH TOUGHNESS
Abstract
Ni--Cr--Nb--P--B alloys optionally bearing Si and metallic
glasses formed from said alloys are disclosed, where the alloys
have a critical rod diameter of at least 5 mm and the metallic
glasses demonstrate a notch toughness of at least 96 MPa
m.sup.1/2.
Inventors: |
Na; Jong Hyun; (Pasadena,
CA) ; Han; Kyung-Hee; (Pasadena, CA) ; Launey;
Maximilien; (Pasadena, CA) ; Demetriou; Marios
D.; (West Hollywood, CA) ; Johnson; William L.;
(San Marino, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Glassimetal Technology, Inc. |
Pasadena |
CA |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20180258516 A1 |
September 13, 2018 |
|
|
Family ID: |
63446168 |
Appl. No.: |
15/916046 |
Filed: |
March 8, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62469348 |
Mar 9, 2017 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 45/04 20130101;
C22C 2200/02 20130101 |
International
Class: |
C22C 45/04 20060101
C22C045/04 |
Claims
1. An alloy capable of forming a metallic glass represented by the
following formula (subscripts w, x, y, and z denote deviations from
a nominal concentration in atomic percentages, while a denotes an
atomic fraction):
Ni.sub.(95-w-x-y-z)Cr.sub.2+wNb.sub.3+x(P.sub.1-aSi.sub.a).sub.yB.sub.z
Eq. (1) -1.5.ltoreq.w<0.5; -0.5.ltoreq.x.ltoreq.1;
2.6.ltoreq.z.ltoreq.4; 20.2+0.2w-0.65|x|-z.ltoreq.y.ltoreq.20.8-z;
0.ltoreq.a.ltoreq.0.1; wherein the critical rod diameter of the
alloy is at least 5 mm; and wherein the notch toughness of the
metallic glasses formed from the alloy is at least 96 MPa
m.sup.1/2.
2. The alloy of claim 1, wherein -1.ltoreq.w<0.5.
3. The alloy of claim 1, wherein -0.4.ltoreq.x.ltoreq.0.8.
4. The alloy of claim 1, wherein -2.8.ltoreq.z.ltoreq.3.8.
5. The alloy of claim 1, wherein
20.2+0.2w-0.65|x|-z.ltoreq.y.ltoreq.20.7-z.
6. The alloy of claim 1, wherein 0.ltoreq.a.ltoreq.0.8.
7. The alloy of claim 1, wherein up to 2 atomic percent of Ni is
substituted by Co, Fe, Cu, Ru, Re, Pd, Pt, or a combination
thereof.
8. The alloy of claim 1, wherein up to 1 atomic percent of Cr is
substituted by Mn, W, Mo, or a combination thereof.
9. The alloy of claim 1, wherein up to 1.5 atomic percent of Nb is
substituted by Ta, V, or a combination thereof.
10. The alloy of claim 1, wherein the atomic concentration of Nb is
less than 3.6 percent and the notch toughness of the metallic glass
formed from the alloy is at least 100 MPa m.sup.1/2.
11. The alloy of claim 1, wherein the atomic concentration of B is
less than 3.8 percent and the notch toughness of the metallic glass
formed from the alloy is at least 100 MPa m.sup.1/2.
12. The alloy of claim 1, wherein the atomic concentration of
metalloids is in the range of 20 to 20.7 percent and the notch
toughness of the metallic glass formed from the alloy is at least
100 MPa m.sup.1/2.
13. A metallic glass formed of the alloy of claim 1.
14. An alloy capable of forming a metallic glass comprising: Cr in
an atomic percent of 2 with a variance w of from -1.5 to less than
0.5; Nb in an atomic percent of 3 with a variance x of from -0.5 to
1; B in an atomic percent z ranging from 2.6 to 4; P and optionally
Si, wherein the combined P and Si atomic percent ranges from
20.2+0.2w-0.65|x|-z to 20.8-z, wherein the atomic fraction of Si in
the combined P and Si atomic percent ranges from 0 to 0.1; wherein
the balance is Ni and incidental impurities; wherein the critical
rod diameter of the alloy is at least 5 mm; and wherein the notch
toughness of the metallic glass formed from the alloy is at least
96 MPa m.sup.1/2.
15. The alloy of claim 12, further comprising up to 20 atomic
percent Co.
16. The alloy of claim 12, further comprising up to 10 atomic
percent of Co, Fe, Cu, or combinations thereof.
17. The alloy of claim 12, further comprising up to 2 atomic
percent pf Fe, Mn, W, Mo, Ru, Re, Cu, Pd, Pt, Ta, V, or
combinations thereof.
18. A metallic glass formed of the alloy of claim 14.
19. An alloy selected from a group consisting of
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.75Si.sub.0.25B.sub.3.3,
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.25Si.sub.0.75B.sub.3.3,
Ni.sub.75Cr.sub.2Nb.sub.2.7P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.74.6Cr.sub.2Nb.sub.3.1 P.sub.16.5Si.sub.0.5 B.sub.3.3,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5 B.sub.3.3,
Ni.sub.74.2Cr.sub.2Nb.sub.3.5P.sub.16.5Si.sub.0.5 B.sub.3.3,
Ni.sub.74Cr.sub.2Nb.sub.3.7P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.73.8Cr.sub.2Nb.sub.3.9P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.17.1Si.sub.0.5B.sub.2.7,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.9Si.sub.0.5B.sub.2.9,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.7Si.sub.0.5B.sub.3.1,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.3Si.sub.0.5B.sub.3.5,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3 P.sub.16.1Si.sub.0.5 B.sub.3.7,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.15.9Si.sub.0.5 B.sub.3.9,
Ni.sub.74.21Cr.sub.2Nb.sub.3.29 P.sub.16.66Si.sub.0.51B.sub.3.33,
Ni.sub.74.03Cr.sub.1.99
Nb.sub.3.28P.sub.16.83Si.sub.0.51B.sub.3.36, Ni.sub.75.4Cr.sub.1
Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.74.9Cr.sub.1.5Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3, and
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3.
20. A method for forming an article of a metallic glass comprising
an alloy of claim 1, the method comprising: melting the alloy to
form a molten alloy; and subsequently quenching the molten alloy at
a cooling rate sufficiently high to prevent crystallization of the
alloy.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This patent application claims the benefit under 35 U.S.C.
.sctn. 119(e) of U.S. Patent Application No. 62/469,348, entitled
"BULK NICKEL-NIOBIUM-PHOSPHORUS-BORON GLASSES BEARING LOW FRACTIONS
OF CHROMIUM AND EXHIBITING HIGH TOUGHNESS," filed on Mar. 9, 2017,
which is incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The disclosure relates to Ni--Nb--P--B alloys bearing low
fractions of Cr and optionally Si that are capable of forming a
metallic glass in bulk dimensions, and wherein the metallic glasses
demonstrates a high toughness.
BACKGROUND
[0003] Ni--Cr--Nb--P--B alloys optionally bearing Si capable of
forming bulk metallic glass rods with critical rod diameters
greater than 3 mm have been disclosed in U.S. patent application
Ser. No. 13/592,095, entitled "Bulk Nickel-Based Chromium and
Phosphorus Bearing Metallic Glasses," filed on Aug. 22, 2012, and
issued as U.S. Pat. No. 9,085,814 on Jul. 21, 2015, the disclosure
of which is incorporated herein by reference in its entirety. In
this application it is also shown that within the disclosed range
the toughness varies with the Cr content, attaining a peak of 94.56
MPa m.sup.1/2 over a very narrow range around 5 atomic percent Cr.
The toughness drops significantly when the Cr content varies above
or below the 5 atomic percent. This peak in toughness however comes
at the expense of glass-forming ability, as the single alloy
demonstrating the peak toughness has a critical rod diameter of
just 5 mm.
[0004] Ni--Cr--Nb--P--B alloys optionally bearing Si capable of
forming bulk metallic glass rods with critical rod diameters of at
least 3 mm have been disclosed in U.S. patent application Ser. No.
14/540,815, entitled "Bulk Nickel-Chromium-Phosphorus Glasses
Bearing Niobium and Boron Exhibiting High Strength and/or High
Thermal Stability of the Supercooled Liquid Region," filed on Nov.
13, 2014 and issued as U.S. Pat. No. 9,863,024 on Jan. 8, 2018, the
disclosure of which is incorporated herein by reference in its
entirety. In this application it is also shown that toughness
increases as the atomic concentration of B drops below 3 atomic
percent, but the increase in toughness comes at the expense of
glass-forming ability. Specifically, a very narrow range is
presented where notch toughness and critical rod diameter are both
high, where a single alloy demonstrates a notch toughness of 95.1
MPa m.sup.1/2 and a critical rod diameter of 6 mm. When the B
content varies above or below that value, either toughness or
glass-forming ability drops significantly.
[0005] Ni--Cr--Nb--P--B alloys optionally bearing Si capable of
forming bulk metallic glass rods have also been disclosed in U.S.
patent application Ser. No. 14/067,521, entitled "Bulk Nickel-Based
Chromium and Phosphorus Bearing Metallic Glasses with High
Toughness," filed on Oct. 30, 2013, the disclosure of which is
incorporated herein by reference in its entirety. A combination of
high glass-forming ability and high toughness is achieved within a
range of Nb and Cr concentrations, where critical rod diameters
exceed 6 mm and notch toughness values exceed 70 MPa m.sup.1/2.
Alloys in the disclosed range demonstrate a notch toughness greater
than 70 MPa m.sup.1/2 and up to 85.5 MPa m.sup.1/2, and a critical
rod diameter greater than 6 mm and up to 11 mm.
[0006] The Ser. Nos. 13/592,095 and 14/540,815 applications
therefore disclose Ni--Cr--Nb--P--B alloys optionally bearing Si
with toughness varying sharply with composition, demonstrating a
peak of about 95 MPa m.sup.1/2 over a very narrow range, while the
alloys that demonstrate the peak toughness of about 95 MPa
m.sup.1/2 have a critical rod diameter limited to 5-6 mm. On the
other hand, the Ser. No. 14/067,521 application discloses
Ni--Cr--Nb--P--B alloys optionally bearing Si that have both a high
toughness and a high glass-forming ability over a broader region.
While the glass-forming ability extends to as high as 11 mm, the
notch toughness is limited to about 85 MPa m.sup.1/2.
[0007] There still remains a need to identify a compositional range
of Ni--Cr--Nb--P--B alloys optionally bearing Si where the alloys
demonstrate very high toughness and good glass-forming ability over
a fairly broad compositional range.
BRIEF SUMMARY
[0008] The disclosure is directed to Ni--Cr--Nb--P--B alloys and
metallic glasses, where over the disclosed range the alloys
demonstrate good glass-forming ability while the metallic glasses
formed from the alloys demonstrate a high toughness. Specifically,
the alloys of the disclosure demonstrate a critical rod diameter in
excess of 5 mm, while the metallic glasses formed from the alloys
demonstrate a notch toughness greater than 95 MPa m.sup.1/2.
[0009] In one embodiment, the disclosure is directed to an alloy
capable of forming a metallic glass represented by the following
formula (subscripts w, x, y, and z denote deviations from a nominal
concentration in atomic percentages, while a denotes an atomic
fraction):
Ni.sub.(95-w-x-y-z)Cr.sub.2+wNb.sub.3+x(P.sub.1-aSi.sub.a).sub.yB.sub.z
Eq. (1)
[0010] where: [0011] -1.5.ltoreq.w<0.5; [0012]
-0.5.ltoreq.x.ltoreq.1; [0013] 2.6.ltoreq.z.ltoreq.4; [0014]
20.2+0.2w-0.65|x|-z.ltoreq.y.ltoreq.20.8-z; [0015]
0.ltoreq.a.ltoreq.0.1; [0016] where the critical rod diameter of
the alloy is at least 5 mm; and [0017] where the notch toughness of
the metallic glass formed from the alloy is at least 96 MPa
m.sup.1/2.
[0018] In another embodiment, -1.ltoreq.w<0.5.
[0019] In another embodiment, -0.5.ltoreq.w<0.5.
[0020] In another embodiment, -0.4.ltoreq.x.ltoreq.0.8.
[0021] In another embodiment, -0.3.times.0.6.
[0022] In another embodiment, -2.7.ltoreq.z.ltoreq.3.8.
[0023] In another embodiment, -2.8.ltoreq.z.ltoreq.3.8.
[0024] In another embodiment,
20.2+0.2w-0.65|x|-z.ltoreq.y.ltoreq.20.7-z.
[0025] In another embodiment,
20.2+0.2w-0.65|x|-z.ltoreq.y.ltoreq.20.6-z.
[0026] In another embodiment, 0.ltoreq.a.ltoreq.0.8.
[0027] In another embodiment, 0.ltoreq.a.ltoreq.0.6.
[0028] In another embodiment, up to 2 atomic percent of Ni is
substituted by Co, Fe, Cu, Ru, Re, Pd, Pt, or a combination
thereof.
[0029] In another embodiment, up to 1 atomic percent of Cr is
substituted by Mn, W, Mo, or a combination thereof.
[0030] In another embodiment, up to 1.5 atomic percent of Nb is
substituted by Ta, V, or a combination thereof.
[0031] In another embodiment, the disclosure is directed to an
alloy capable of forming a metallic glass comprising:
[0032] Cr in an atomic percent of 2 with a variance w of from -1.5
to less than 0.5;
[0033] Nb in an atomic percent of 3 with a variance x of from -0.5
to 1;
[0034] B in an atomic percent z ranging from 2.6 to 4;
[0035] P and optionally Si, where the combined P and Si atomic
percent ranges from 20.2+0.2w-0.65|x|-z to 20.8-z, where the atomic
fraction of Si in the combined P and Si atomic percent ranges from
0 to 0.1;
[0036] where the balance is Ni and incidental impurities;
[0037] where the critical rod diameter of the alloy is at least 5
mm; and
[0038] where the notch toughness of the metallic glass formed from
the alloy is at least 96 MPa m.sup.1/2.
[0039] In some aspects, an alloy can include a small amount of
incidental impurities. The impurity elements can be present, for
example, as a byproduct of processing and manufacturing. The
impurities can be less than or equal to about 2 wt %, alternatively
less than or equal about 1 wt %, alternatively less than or equal
about 0.5 wt %, alternatively less than or equal about 0.1 wt
%.
[0040] In another embodiment, the alloy additionally comprises Co
in an atomic fraction of up to 20%.
[0041] In another embodiment, up to 20 atomic percent of Ni is
substituted by Co.
[0042] In another embodiment, the alloy additionally comprises Co,
Fe, Cu, or combinations thereof, in an atomic fraction of up to
10%.
[0043] In another embodiment, up to 10 atomic percent of Ni is
substituted by Co, Fe, Cu, or combinations thereof.
[0044] In another embodiment, the alloy additionally comprises Co,
Fe, Mn, W, Mo, Ru, Re, Cu, Pd, Pt, Ta, V, or combinations thereof,
in an atomic fraction of up to 2%.
[0045] In another embodiment, up to 2 atomic percent of Ni is
substituted by Co, Fe, Cu, Ru, Re, Cu, Pd, Pt, or combinations
thereof.
[0046] In another embodiment, up to 1 atomic percent of Cr is
substituted by Mn, W, Mo, or combinations thereof.
[0047] In another embodiment, up to 1.5 atomic percent of Nb is
substituted by Ta, V, or combinations thereof.
[0048] In another embodiment, the critical rod diameter of the
alloy is at least 6 mm.
[0049] In another embodiment, the critical rod diameter of the
alloy is at least 7 mm.
[0050] In another embodiment, the critical rod diameter of the
alloy is at least 8 mm.
[0051] In another embodiment, the notch toughness of the metallic
glass formed from the alloy is at least 96 MPa m.sup.1/2.
[0052] In another embodiment, the notch toughness of the metallic
glass formed from the alloy is at least 97 MPa m.sup.1/2.
[0053] In another embodiment, the notch toughness of the metallic
glass formed from the alloy is at least 98 MPa m.sup.1/2.
[0054] In another embodiment, the notch toughness of the metallic
glass formed from the alloy is at least 99 MPa m.sup.1/2.
[0055] In another embodiment, the notch toughness of the metallic
glass formed from the alloy is at least 100 MPa m.sup.1/2.
[0056] In another embodiment, the atomic concentration of Nb is
less than 3.6 percent, and the notch toughness of the metallic
glass formed from the alloy is at least 100 MPa m.sup.1/2.
[0057] In another embodiment, the atomic concentration of B is less
than 3.8 percent, and the notch toughness of the metallic glass
formed from the alloy is at least 100 MPa m.sup.1/2.
[0058] In another embodiment, the atomic concentration of
metalloids is in the range of 20 to 20.7 percent, and the notch
toughness of the metallic glass formed from the alloy is at least
100 MPa m.sup.1/2.
[0059] In another embodiment, the atomic concentration of Cr is not
more than 2 percent, and the notch toughness of the metallic glass
formed from the alloy is at least 100 MPa m.sup.1/2.
[0060] The disclosure is also directed to an alloy capable of
forming a metallic glass having compositions selected from a group
consisting of
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.75Si.sub.0.26B.sub.3.3,
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.25Si.sub.0.75B.sub.3.3,
Ni.sub.75Cr.sub.2Nb.sub.2.7P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.74.6Cr.sub.2Nb.sub.3.1 P.sub.16.5Si.sub.0.5 B.sub.3.3,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5 B.sub.3.3,
Ni.sub.74.2Cr.sub.2Nb.sub.3.5P.sub.16.5Si.sub.0.5 B.sub.3.3,
Ni.sub.74Cr.sub.2Nb.sub.3.7P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.73.8Cr.sub.2Nb.sub.3.9P.sub.16.5Si.sub.0.5B.sub.3.3,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.17.1Si.sub.0.5B.sub.2.7,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3 P.sub.16.9Si.sub.0.5 B.sub.2.9,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.7Si.sub.0.5 B.sub.3.1,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.3Si.sub.0.5B.sub.3.5,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.1Si.sub.0.5B.sub.3.7,
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.15.9Si.sub.0.5 B.sub.3.9,
Ni.sub.74.21 Cr.sub.2Nb.sub.3.29P.sub.16.66Si.sub.0.51 B.sub.3.33,
Ni.sub.74.03Cr.sub.1.99 Nb.sub.3.28 P.sub.16.83Si.sub.0.51
B.sub.3.36 Ni.sub.75.4Cr.sub.1 Nb.sub.3.3
P.sub.16.5Si.sub.0.5B.sub.3.3, Ni.sub.74.9Cr.sub.1.5 Nb.sub.3.3
P.sub.16.5Si.sub.0.5 B.sub.3.3, and
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3.
[0061] The disclosure is further directed to a metallic glass
having any of the above formulas and/or formed of any of the
foregoing alloys.
[0062] In a further embodiment, a method is provided for forming an
article of a metallic glass comprising an alloy according to the
present disclosure. The method includes melting the alloy to form a
molten alloy and subsequently quenching the molten alloy at a
cooling rate sufficiently high to prevent crystallization of the
alloy.
[0063] In yet another embodiment, the molten alloy is fluxed with a
reducing agent prior to the quenching.
[0064] In yet another embodiment, the molten alloy is fluxed with
boron oxide prior to the quenching.
[0065] In yet another embodiment, the temperature of the molten
alloy prior to quenching is at least 100.degree. C. above the
liquidus temperature of the alloy.
[0066] In yet another embodiment, the temperature of the molten
alloy prior to quenching is at least 1100.degree. C.
[0067] Additional embodiments and features are set forth in part in
the description that follows, and in part will become apparent to
those skilled in the art upon examination of the specification or
may be learned by the practice of the disclosed subject matter. A
further understanding of the nature and advantages of the
disclosure may be realized by reference to the remaining portions
of the specification and the drawings, which forms a part of this
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0068] The description will be more fully understood with reference
to the following figures and data graphs, which are presented as
various embodiments of the disclosure and should not be construed
as a complete recitation of the scope of the disclosure,
wherein:
[0069] FIG. 1 provides a data plot showing the effect of varying
the Si atomic concentration at the expense of P according to the
formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 on
the critical rod diameter of the alloys in accordance with
embodiments of the disclosure.
[0070] FIG. 2 provides a data plot showing the effect of varying
the Si atomic concentration at the expense of P according to the
formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 on
the notch toughness of the metallic glasses in accordance with
embodiments of the disclosure.
[0071] FIG. 3 provides calorimetry scans for sample metallic
glasses
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 in
accordance with embodiments of the disclosure. The glass transition
temperature T.sub.g, crystallization temperature T.sub.x, solidus
temperature T.sub.s, and liquidus temperature T.sub.l are indicated
by arrows.
[0072] FIG. 4 provides a data plot showing the effect of varying
the Nb atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 on the
critical rod diameter of the alloys in accordance with embodiments
of the disclosure.
[0073] FIG. 5 provides a data plot showing the effect of varying
the Nb atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 on the
notch toughness of the metallic glasses in accordance with
embodiments of the disclosure.
[0074] FIG. 6 provides calorimetry scans for sample metallic
glasses
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 in
accordance with embodiments of the disclosure. The glass transition
temperature T.sub.g, crystallization temperature T.sub.x, solidus
temperature T.sub.s, and liquidus temperature T.sub.l are indicated
by arrows.
[0075] FIG. 7 provides a data plot showing the effect of varying
the B atomic concentration at the expense of P according to the
formula Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z
on the critical rod diameter of the alloys in accordance with
embodiments of the disclosure.
[0076] FIG. 8 provides a data plot showing the effect of varying
the B atomic concentration at the expense of P according to the
formula Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z
on the notch toughness of the metallic glasses in accordance with
embodiments of the disclosure.
[0077] FIG. 9 provides calorimetry scans for sample metallic
glasses Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z
in accordance with embodiments of the disclosure. The glass
transition temperature T.sub.g, crystallization temperature
T.sub.x, solidus temperature T.sub.s, and liquidus temperature
T.sub.l are indicated by arrows.
[0078] FIG. 10 provides a data plot showing the effect of varying
the metalloid atomic concentration at the expense of metals
according to the formula
Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.s-
ub.0.025B.sub.0.162].sub.y+z on the critical rod diameter of the
alloys in accordance with embodiments of the disclosure.
[0079] FIG. 11 provides a data plot showing the effect of varying
the metalloid atomic concentration at the expense of metals
according to the formula
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.-
sub.0.025B.sub.0.162].sub.y+z on the notch toughness of the
metallic glasses in accordance with embodiments of the
disclosure.
[0080] FIG. 12 provides calorimetry scans for sample metallic
glasses
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.sub.0.02-
5B.sub.0.162].sub.y+z in accordance with embodiments of the
disclosure. The glass transition temperature T.sub.g,
crystallization temperature T.sub.x, solidus temperature T.sub.s,
and liquidus temperature T.sub.l are indicated by arrows.
[0081] FIG. 13 provides a data plot showing the effect of varying
the Cr atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 on
the critical rod diameter of the alloys in accordance with
embodiments of the disclosure.
[0082] FIG. 14 provides a data plot showing the effect of varying
the Cr atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 on
the notch toughness of the metallic glasses in accordance with
embodiments of the disclosure.
[0083] FIG. 15 provides calorimetry scans for sample metallic
glasses
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 in
accordance with embodiments of the disclosure. The glass transition
temperature T.sub.g, crystallization temperature T.sub.x, solidus
temperature T.sub.s, and liquidus temperature T.sub.l are indicated
by arrows.
[0084] FIG. 16 presents a compositional range plot in two
compositional directions, y and z, with y representing the combined
atomic concentrations of (P, Si) and x representing the atomic
concentration of B, when the atomic concentrations of Cr, Nb, and
Si are held constant at 2, 3.3, and 0.5 atomic percent,
respectively, according to equation
Ni.sub.94.7-y-zCr.sub.2Nb.sub.3.3P.sub.y-0.5Si.sub.0.5B.sub.z in
accordance with embodiments of the disclosure.
[0085] FIG. 17 illustrates a 7 mm rod of metallic glass
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3
processed by water quenching the high temperature melt in a fused
silica tube having a wall thickness of 1 mm in accordance with
embodiments of the disclosure.
[0086] FIG. 18 illustrates an X-ray diffractogram verifying the
amorphous structure of a 7 mm rod of sample metallic glass
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3
processed by water quenching the high temperature melt in a fused
silica tube having a wall thickness of 1 mm in accordance with
embodiments of the disclosure.
DETAILED DESCRIPTION
[0087] The disclosure is directed to alloys, metallic glasses, and
methods of making and using the same. In some aspects, the alloys
are described as capable of forming metallic glasses having certain
characteristics. It is intended, and will be understood by those
skilled in the art, that the disclosure is also directed to
metallic glasses formed of the disclosed alloys described
herein.
[0088] The disclosure provides a range of Ni--Cr--Nb--P--B alloys
optionally bearing Si where the metallic glasses formed from the
alloys demonstrate a notch toughness in excess of 95 MPa m.sup.1/2
and the alloys have a critical rod diameter in excess of 5 mm.
Definitions
[0089] In the disclosure, the glass-forming ability of each alloy
is quantified by the "critical rod diameter", defined as maximum
rod diameter in which the amorphous phase can be formed when
processed by a method of water quenching a quartz tube with a 0.5
mm thick wall containing the molten alloy.
[0090] A "critical cooling rate", which is defined as the cooling
rate to avoid crystallization and form the amorphous phase of the
alloy (i.e. a metallic glass), determines the "critical rod
diameter." The lower the critical cooling rate of an alloy, the
larger its critical rod diameter. The critical cooling rate R.sub.c
in K/s and critical rod diameter in mm are related via the
following approximate empirical formula:
R.sub.c=1000/d.sub.c.sup.2 Eq. (2)
For example, according to Eq. (2), the critical cooling rate for an
alloy having a critical rod diameter of about 3 mm is only about
10.sup.2 K/s.
[0091] Generally, three categories are known in the art for
identifying the ability of an alloy to form a metallic glass (i.e.
to bypass the stable crystal phase and form an amorphous phase).
Alloys having critical cooling rates in excess of 10.sup.12 K/s are
typically referred to as non-glass formers, as it is very difficult
to achieve such cooling rates and form the amorphous phase over a
meaningful cross-section thickness (i.e. at least 1 micrometer).
Alloys having critical cooling rates in the range of 10.sup.5 to
10.sup.12 K/s are typically referred to as marginal glass formers,
as they are able to form glass over thicknesses ranging from 1 to
100 micrometers according to Eq. (2). Alloys having critical
cooling rates on the order of 10.sup.3 or less, and as low as 1 or
0.1 K/s, are typically referred to as bulk glass formers, as they
are able to form glass over thicknesses ranging from 1 millimeter
to several centimeters. The glass-forming ability of an alloy (and
by extension its critical cooling rate and critical rod diameter)
is, to a very large extent, dependent on the composition of the
alloy. The compositional ranges for alloys capable of forming
marginal glass formers are considerably broader than those for
forming bulk glass formers.
[0092] The notch toughness, defined as the stress intensity factor
at crack initiation K.sub.q, is the measure of the material's
ability to resist fracture in the presence of a notch. The notch
toughness is a measure of the work required to propagate a crack
originating from a notch. A high K.sub.q ensures that the material
will be tough in the presence of defects.
[0093] The width of the supercooled region .DELTA.T.sub.x is
defined as the difference between the crystallization temperature
T.sub.x and the glass transition temperature T.sub.g of the
metallic glass, .DELTA.T.sub.x=T.sub.x-T.sub.g, measured at heating
rate of 20 K/min. A large .DELTA.T.sub.x value implies a large
thermal stability of the supercooled liquid and designates an
ability of the metallic glass to be formed into an article by
thermoplastic processing at temperatures above T.sub.g.
[0094] Description of Alloy and Metallic Glass Compositions
[0095] In accordance with the provided disclosure and drawings,
Ni--Cr--Nb--P--B alloys optionally bearing Si and metallic glasses
formed from these alloys are provided within a well-defined
compositional range requiring very low cooling rates to form
metallic glasses, thereby allowing for bulk metallic glass
formation such that metallic glass rods with critical rod diameters
of at least 5 mm can be formed, and where the metallic glasses
formed from the disclosed alloys demonstrate a notch toughness
greater than 95 MPa m.sup.1/2.
[0096] Ni--Cr--Nb--P--B alloys optionally bearing Si that fall
within the compositional ranges of the disclosure having a critical
rod diameter of at least 5 mm forming metallic glasses that
demonstrate notch toughness of at least 96 MPa m.sup.1/2 can be
represented by the following formula (subscripts w, x, y, and z
denote deviations from a nominal concentration in atomic
percentages, while a denotes an atomic fraction):
Ni.sub.(95-w-x-y-z)Cr.sub.2+wNb.sub.3+x(P.sub.1-aSi.sub.a).sub.yB.sub.z
Eq. (1) [0097] -1.5.ltoreq.w.ltoreq.0.5; [0098]
-0.5.ltoreq.x.ltoreq.1; [0099] 2.6.ltoreq.z.ltoreq.4; [0100]
20.2+0.2w-0.65|x|-z.ltoreq.y.ltoreq.20.8-z; [0101]
0.ltoreq.a.ltoreq.0.1; [0102] where the critical rod diameter of
the alloys is at least 5 mm; and [0103] where the notch toughness
of the metallic glasses formed from the alloys is at least 96 MPa
m.sup.1/2.
[0104] Specific embodiments of metallic glasses formed of alloys
having compositions according to the formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3,
where a ranges from 0 to 1/17, are presented in Table 1. Note that
parameter c in formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 is
equivalent to parameter a in Eq. (1). The corresponding critical
rod diameters and notch toughness values are also listed in Table
1.
[0105] FIG. 1 provides a data plot showing the effect of varying
the Si atomic concentration at the expense of P according to the
formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 on
the critical rod diameter of the alloys. The critical rod diameter
is shown to increase slightly from 4 mm to a peak value of 6 mm as
the Si concentration increases from 0 to 0.5 atomic percent, and
then decreases to 4 mm as the Si concentration increases further to
1 atomic percent. The critical rod diameter is at least 5 mm when
Si concentration ranges from 0.25 to 0.75 atomic percent.
[0106] FIG. 2 provides a data plot showing the effect of varying
the Si atomic concentration at the expense of P according to the
formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 on
the notch toughness of the metallic glasses. The notch toughness is
shown to be greater than 100 MPa m.sup.1/2 when the Si
concentration is in the range of 0 to 1 atomic percent, and greater
than 105 MPa m.sup.1/2 when the Si concentration is in the range of
0 to 0.75 atomic percent.
TABLE-US-00001 TABLE 1 Sample alloys demonstrating the effect of
increasing the Si atomic concentration at the expense of P
according to the formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 on
the critical rod diameter and notch toughness of the sample
metallic glass formed of the sample alloys. Notch Critical Rod
Toughness Sample Composition Diameter [mm] K.sub.Q (MPa m.sup.1/2)
1 Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.17B.sub.3.3 4 106.9 .+-. 11.7
2 Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.75Si.sub.0.25B.sub.3.3 5
109.1 .+-. 2.3 3
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.5Si.sub.0.5B.sub.3.3 6 106.4
.+-. 3.5 4
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.25Si.sub.0.75B.sub.3.3 5
106.9 .+-. 6.8 5
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16Si.sub.1B.sub.3.3 4 101.3 .+-.
2.9
[0107] FIG. 3 provides calorimetry scans for sample metallic
glasses
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 in
accordance with embodiments of the disclosure. The glass transition
temperature T.sub.g, crystallization temperature T.sub.x, solidus
temperature T.sub.s, and liquidus temperature T.sub.l are indicated
by arrows in FIG. 3. Table 2 lists the glass transition temperature
T.sub.g, crystallization temperature T.sub.x, solidus temperature
T.sub.s, and liquidus temperature T.sub.l along with the respective
.DELTA.T.sub.x value for sample metallic glasses
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 in
accordance with embodiments of the disclosure.
[0108] As shown in Table 2, the value for the metallic glass
containing 0 atomic percent Si (Sample 1) is 38.9.degree. C., while
the value for the metallic glass containing 0.25 atomic percent Si
(Sample 2) is 35.8.degree. C. and the value for the metallic glass
containing 0.5 atomic percent Si (Sample 2) is 37.3.degree. C.,
which are smaller than the Si-free metallic glass (Sample 1).
However, the value for the metallic glass containing 0.75 atomic
percent Si (Sample 4) is 39.2.degree. C., which is close to the
Si-free metallic glass. The value for the metallic glass containing
1 atomic percent Si (Sample 5) drops to 37.1.degree. C. For sample
metallic glasses where the Si concentration is up to 1,
.DELTA.T.sub.x is at least 35.degree. C.
TABLE-US-00002 TABLE 2 Sample alloys demonstrating the effect of
increasing the Si atomic concentration at the expense of P
according to the formula
Ni.sub.74.8Cr.sub.2Nb.sub.2.9(P.sub.1-aSi.sub.a).sub.17B.sub.3.3 on
the glass transition temperature T.sub.g, crystallization
temperature T.sub.x, solidus temperature T.sub.s, liquidus
temperature T.sub.l and on .DELTA.T.sub.x (=T.sub.x - T.sub.g).
Sample Composition T.sub.g (.degree. C.) T.sub.x (.degree. C.)
.DELTA.T.sub.x (.degree. C.) T.sub.s (.degree. C.) T.sub.l
(.degree. C.) 1 Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.17B.sub.3.3
395.8 434.7 38.9 835.5 892.4 2
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.75Si.sub.0.25B.sub.3.3 396.7
432.5 35.8 835.0 877.9 3
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.5Si.sub.0.5B.sub.3.3 394.9
432.2 37.3 834.9 875.3 4
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.25Si.sub.0.75B.sub.3.3 396.0
435.2 39.2 835.2 892.7 5
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16Si.sub.1B.sub.3.3 400.4 437.5
37.1 836.6 892.2
[0109] Specific embodiments of metallic glasses formed of alloys
having compositions according to the formula
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3, where
x ranges from -0.5 to +1.5, are presented in Table 3. The
corresponding critical rod diameters and notch toughness values are
also listed in Table 3.
[0110] FIG. 4 provides a data plot showing the effect of varying
the Nb atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 on the
critical rod diameter of the alloys. The critical rod diameter is
shown to increase from 2 to 7 mm as the Nb concentration increases
from 2.5 to about 3.2 atomic percent, and then decreases to 2 mm as
the Nb concentration increases further to 4.5 atomic percent. The
critical rod diameter is at least 5 mm in the range where the Nb
content varies from 2.7 to 4.1 atomic percent.
[0111] FIG. 5 provides a data plot showing the effect of varying
the Nb atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 on the
notch toughness of the metallic glasses. The notch toughness is
shown to increase monotonically with decreasing Nb content, from
64.1 MPa m.sup.1/2 for the alloy containing 4.1 atomic percent Nb
to 106.9 MPa m.sup.1/2 for the alloy containing 2.7 atomic percent
Nb. The notch toughness is at least 96 MPa m.sup.1/2 in the range
where the Nb content is less than about 4 atomic percent, while is
at least 100 MPa m.sup.1/2 when the Nb content is less than about
3.6 atomic percent.
TABLE-US-00003 TABLE 3 Sample alloys demonstrating the effect of
increasing the Nb atomic concentration at the expense of Ni
according to the formula
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 on the
critical rod diameter and notch toughness of the sample metallic
glass formed of the sample alloys. Notch Critical Rod Toughness
Sample Composition Diameter [mm] K.sub.Q (MPa m.sup.1/2) 6
Ni.sub.75.2Cr.sub.2Nb.sub.2.5P.sub.16.5Si.sub.0.5B.sub.3.3 2 -- 7
Ni.sub.75Cr.sub.2Nb.sub.2.7P.sub.16.5Si.sub.0.5B.sub.3.3 5 106.9
.+-. 4.2 3
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.5Si.sub.0.5B.sub.3.3 6 106.4
.+-. 3.5 8
Ni.sub.74.6Cr.sub.2Nb.sub.3.1P.sub.16.5Si.sub.0.5B.sub.3.3 6 100.1
.+-. 1.9 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 7 101.9
.+-. 4.4 10
Ni.sub.74.2Cr.sub.2Nb.sub.3.5P.sub.16.5Si.sub.0.5B.sub.3.3 7 100.4
.+-. 5.2 11
Ni.sub.74Cr.sub.2Nb.sub.3.7P.sub.16.5Si.sub.0.5B.sub.3.3 6 96.9
.+-. 4.1 12
Ni.sub.73.8Cr.sub.2Nb.sub.3.9P.sub.16.5Si.sub.0.5B.sub.3.3 6 95.5
.+-. 4.5 13
Ni.sub.73.6Cr.sub.2Nb.sub.4.1P.sub.16.5Si.sub.0.5B.sub.3.3 5 64.1
.+-. 2.1 14
Ni.sub.73.2Cr.sub.2Nb.sub.4.5P.sub.16.5Si.sub.0.5B.sub.3.3 2 --
[0112] FIG. 6 provides calorimetry scans for sample metallic
glasses
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 in
accordance with embodiments of the disclosure. The glass transition
temperature T.sub.g, crystallization temperature T.sub.x, solidus
temperature T.sub.s, and liquidus temperature T.sub.l are indicated
by arrows in FIG. 6. Table 4 lists the glass transition temperature
T.sub.g, crystallization temperature T.sub.x, solidus temperature
T.sub.s, and liquidus temperature T.sub.l along with the respective
.DELTA.T.sub.x value for sample metallic glasses
Ni.sub.74.7-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3 in
accordance with embodiments of the disclosure.
[0113] As shown in Table 4, the value for the metallic glass
containing 3.3 atomic percent Nb (Sample 9) is 36.7.degree. C., and
the value for the metallic glass containing 3.7 atomic percent Nb
(Sample 11) is 40.5.degree. C. The value for the metallic glass
containing 4.1 atomic percent Nb (Sample 13) is 34.0.degree. C.,
and the value for the metallic glass containing 4.5 atomic percent
Nb (Sample 14) is 30.5.degree. C. For sample metallic glasses where
the Nb concentration is equal to or less than 4 atomic percent,
.DELTA.T.sub.x is at least 35.degree. C.
TABLE-US-00004 TABLE 4 Sample alloys demonstrating the effect of
increasing the Nb atomic concentration at the expense of Ni
according to the formula
Ni.sub.74.7.sub.-xCr.sub.2Nb.sub.3+xP.sub.16.5Si.sub.0.5B.sub.3.3
on the glass transition temperature T.sub.g, crystallization
temperature T.sub.x, solidus temperature T.sub.s, liquidus
temperature T.sub.l and on .DELTA.T.sub.x (=T.sub.x - T.sub.g).
Sample Composition T.sub.g (.degree. C.) T.sub.x (.degree. C.)
.DELTA.T.sub.x (.degree. C.) T.sub.s (.degree. C.) T.sub.l
(.degree. C.) 6
Ni.sub.75.2Cr.sub.2Nb.sub.2.5P.sub.16.5Si.sub.0.5B.sub.3.3 395.5
430.8 35.3 835.8 885.3 3
Ni.sub.74.8Cr.sub.2Nb.sub.2.9P.sub.16.5Si.sub.0.5B.sub.3.3 394.9
432.2 37.3 834.9 875.3 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 399.8
436.5 36.7 832.5 898.6 11
Ni.sub.74Cr.sub.2Nb.sub.3.7P.sub.16.5Si.sub.0.5B.sub.3.3 398.0
438.5 40.5 831.4 900.5 13
Ni.sub.73.6Cr.sub.2Nb.sub.4.1P.sub.16.5Si.sub.0.5B.sub.3.3 402.3
436.3 34.0 831.9 911.6 14
Ni.sub.73.2Cr.sub.2Nb.sub.4.5P.sub.16.5Si.sub.0.5B.sub.3.3 407.1
437.6 30.5 832.9 915.0
[0114] Specific embodiments of metallic glasses formed of alloys
having compositions according to the formula
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z, where z
ranges from 2.5 to 4.3, are presented in Table 5. The corresponding
critical rod diameters and notch toughness values are also listed
in Table 5.
[0115] FIG. 7 provides a data plot showing the effect of varying
the B atomic concentration at the expense of P according to the
formula Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z
on the critical rod diameter of the alloys. The critical rod
diameter is shown to increase from 2 to 7 mm as the B concentration
increases from 2.5 to about 3 atomic percent, remains constant at 7
mm as the B concentration is in the range of about 3 to about 3.8
atomic percent, and then decreases to 2 mm as the B concentration
increases further to 4.3 atomic percent. The critical rod diameter
is at least 5 mm in the range where the B content varies from about
2.6 to 4.2 atomic percent.
[0116] FIG. 8 provides a data plot showing the effect of varying
the B atomic concentration at the expense of P according to the
formula Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z
on the notch toughness of the metallic glasses. The notch toughness
is shown to increase with decreasing B content, from 65.5 MPa
m.sup.1/2 for the alloy containing 4.3 atomic percent B to 106.2
MPa m.sup.1/2 for the alloy containing 2.9 atomic percent B, and
slightly drops to 105.2 MPa m.sup.1/2 when the B content decreases
further to 2.7 atomic percent. The notch toughness is at least 96
MPa m.sup.1/2 in the range where the B content is less than about 4
atomic percent, and is at least 100 MPa m.sup.1/2 when the B
content is less than about 3.8 atomic percent.
TABLE-US-00005 TABLE 5 Sample alloys demonstrating the effect of
increasing the B atomic concentration at the expense of P according
to the formula
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z on the
critical rod diameter and notch toughness of the sample metallic
glass formed of the sample alloys. Critical Rod Notch Diameter
Toughness Sample Composition [mm] K.sub.Q (MPa m.sup.1/2) 15
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.17.3Si.sub.0.5B.sub.2.5 2 -- 16
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.17.1Si.sub.0.5B.sub.2.7 5 105.2
.+-. 2.0 17
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.9Si.sub.0.5B.sub.2.9 5 106.2
.+-. 3.5 18
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.7Si.sub.0.5B.sub.3.1 7 105.7
.+-. 4.6 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 7 101.9
.+-. 4.4 19
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.3Si.sub.0.5B.sub.3.5 7 101.1
.+-. 2.8 20
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.1Si.sub.0.5B.sub.3.7 7 100.4
.+-. 8.1 21
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.15.9Si.sub.0.5B.sub.3.9 6 96.4
.+-. 2.9 22
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.15.7Si.sub.0.5B.sub.4.1 5 80.7
.+-. 4.0 23
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.15.5Si.sub.0.5B.sub.4.3 4 65.5
.+-. 9.2
[0117] FIG. 9 provides calorimetry scans for sample metallic
glasses Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z
in accordance with embodiments of the disclosure. The glass
transition temperature T.sub.g, crystallization temperature
T.sub.x, solidus temperature T.sub.s, and liquidus temperature
T.sub.l are indicated by arrows in FIG. 9. Table 6 lists the glass
transition temperature T.sub.g, crystallization temperature
T.sub.x, solidus temperature T.sub.s, and liquidus temperature
T.sub.l along with the respective .DELTA.T.sub.x value for sample
metallic glasses
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z in
accordance with embodiments of the disclosure.
[0118] As shown in Table 6, .DELTA.T.sub.x values are larger when
the B concentration exceeds 3.3 atomic percent compared to the
.DELTA.T.sub.x values associated with lower B concentrations.
Specifically, the value for the metallic glass containing 2.5
atomic percent B (Sample 15) is 35.9.degree. C., and the value for
the metallic glass containing 2.9 atomic percent B (Sample 17) is
35.9.degree. C., and the value for the metallic glass containing
3.3 atomic percent B (Sample 9) is 36.7.degree. C. However, the
value for the metallic glass containing 3.7 atomic percent B
(Sample 20) is 41.2.degree. C., and the value for the metallic
glass containing 4.3 atomic percent B (Sample 23) is 41.9.degree.
C. For sample metallic glasses where the B concentration is in the
range of 2.5 to 4 atomic percent, .DELTA.T.sub.x is at least
35.degree. C., while those where the B concentration is in is
greater than 3.3 atomic percent, .DELTA.T.sub.x is at least
40.degree. C.
TABLE-US-00006 TABLE 6 Sample alloys demonstrating the effect of
increasing the B atomic concentration at the expense of P according
to the formula
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8-zSi.sub.0.5B.sub.z on the
glass transition temperature T.sub.g, crystallization temperature
T.sub.x, solidus temperature T.sub.s, liquidus temperature T.sub.l
and on .DELTA.T.sub.x (=T.sub.x - T.sub.g). Sample Composition
T.sub.g (.degree. C.) T.sub.x (.degree. C.) .DELTA.T.sub.x
(.degree. C.) T.sub.s (.degree. C.) T.sub.l (.degree. C.) 15
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.17.3Si.sub.0.5B.sub.2.5 391.4
427.5 35.9 833.1 866.9 17
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.9Si.sub.0.5B.sub.2.9 397.6
433.5 35.9 832.0 877.4 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 399.8
436.5 36.7 832.5 898.6 20
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.1Si.sub.0.5B.sub.3.7 396.6
437.8 41.2 831.0 917.1 23
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.15.5Si.sub.0.5B.sub.4.3 396.6
438.5 41.9 832.8 927.4
[0119] Specific embodiments of metallic glasses formed of alloys
having compositions according to the formula
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.sub.0.02-
5B.sub.0.162].sub.y+z, where y+z (total metalloid concentration;
i.e. the combined concentration of P, Si, and B) ranges from 19.5
to 20.9 atomic percent, are presented in Table 7. The corresponding
critical rod diameters and notch toughness values are also listed
in Table 7.
[0120] FIG. 10 provides a data plot showing the effect of varying
the metalloid atomic concentration at the expense of metals
according to the formula
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.-
sub.0.025B.sub.0.162].sub.y+z on the critical rod diameter of the
alloys. The critical rod diameter is shown to increase from 4 to 7
mm as the metalloid concentration increases from 19.5 to about 20
atomic percent, remains constant at 7 mm as the metalloid
concentration is in the range of about 20 to about 20.4 atomic
percent, and then decreases to 4 mm as the metalloid concentration
increases further to 20.9 atomic percent. The critical rod diameter
is at least 5 mm in the range where the metalloid content varies
from about 19.6 to 20.8 atomic percent.
[0121] FIG. 11 provides a data plot showing the effect of varying
the metalloid atomic concentration at the expense of metals
according to the formula
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.-
sub.0.025B.sub.0.162].sub.y+z on the notch toughness of the
metallic glasses. The notch toughness is shown to increase from
58.2 to 102.3 MPa m.sup.1/2 as the metalloid content increases from
19.5 to about 20.5 atomic percent, and then unexpectedly drops to
52.9 MPa m.sup.1/2 as the metalloid content increases further to
20.9 atomic percent. The notch toughness is at least 96 MPa
m.sup.1/2 in the range where the metalloid content varies from
about 19.9 to 20.8 atomic percent, and is at least 100 MPa
m.sup.1/2 when the metalloid content is in the range of about 20 to
about 20.7 atomic percent.
TABLE-US-00007 TABLE 7 Sample alloys demonstrating the effect of
increasing the metalloid content at the expense of metals according
to the formula
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.sub.0.025-
B.sub.0.162].sub.y+z on the critical rod diameter and notch
toughness of the sample metallic glass formed of the sample alloys.
Critical Rod Notch Diameter Toughness Sample Composition [mm]
K.sub.Q (MPa m.sup.1/2) 24
Ni.sub.75.15Cr.sub.2.02Nb.sub.3.33P.sub.15.85Si.sub.0.48B.sub.3.17
4 58.2 .+-. 1.8 25
Ni.sub.74.96Cr.sub.2.02Nb.sub.3.32P.sub.16.01Si.sub.0.49B.sub.3.2 5
92.0 .+-. 6.1 26
Ni.sub.74.77Cr.sub.2.01Nb.sub.3.32P.sub.16.17Si.sub.0.49B.sub.3.24
6 95.4 .+-. 0.9 27
Ni.sub.74.59Cr.sub.2Nb.sub.3.31P.sub.16.34Si.sub.0.49B.sub.3.27 7
100.2 .+-. 3.6 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 7 101.9
.+-. 4.4 28
Ni.sub.74.21Cr.sub.2Nb.sub.3.29P.sub.16.66Si.sub.0.51B.sub.3.33 6
102.3 .+-. 1.3 29
Ni.sub.74.03Cr.sub.1.99Nb.sub.3.28P.sub.16.83Si.sub.0.51B.sub.3.36
5 97.9 .+-. 2.5 30
Ni.sub.73.84Cr.sub.1.98Nb.sub.3.28P.sub.16.99Si.sub.0.51B.sub.3.4 4
52.9 .+-. 2.6
[0122] FIG. 12 provides calorimetry scans for sample metallic
glasses
[[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.0042].sub.100-y-z[P.sub.0.813Si.sub.0.-
025B.sub.0.162].sub.y+z in accordance with embodiments of the
disclosure. The glass transition temperature T.sub.g,
crystallization temperature T.sub.x, solidus temperature T.sub.s,
and liquidus temperature T.sub.l are indicated by arrows in FIG.
12. Table 8 lists the glass transition temperature T.sub.g,
crystallization temperature T.sub.x, solidus temperature T.sub.s,
and liquidus temperature T.sub.l along with the respective
.DELTA.T.sub.x value for sample metallic glasses
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.sub.0.02-
5B.sub.0.162].sub.y+z in accordance with embodiments of the
disclosure.
[0123] As shown in Table 8, .DELTA.T.sub.x values unexpectedly
increase when the total metalloid concentration is in the range of
greater than 20.3 to 20.9 atomic percent, as compared to the values
associated with metalloid concentrations in the range of 19.5 to
20.3 atomic percent. Specifically, the .DELTA.T.sub.x values for
the metallic glasses containing 19.5 to 20.3 atomic percent
metalloids (Samples 24, 26, 9) is between 32.1.degree. C. and
36.7.degree. C., while the values for the metallic glasses
containing 20.7 to 20.9 atomic percent metalloids (Samples 29, 30)
is between 43.6.degree. C. and 46.1.degree. C. For sample metallic
glasses where the metalloid concentration is greater than 20.5
atomic, .DELTA.T.sub.x is at least 40.degree. C.
TABLE-US-00008 TABLE 8 Sample alloys demonstrating the effect of
increasing the total metalloid concentration at the expense of
metals according to the formula
[Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100-y-z[P.sub.0.813Si.s-
ub.0.025B.sub.0.162].sub.y+z on the glass transition temperature
T.sub.g, crystallization temperature T.sub.x, solidus temperature
T.sub.s, liquidus temperature T.sub.l and on .DELTA.T.sub.x
(=T.sub.x - T.sub.g). Sample Composition T.sub.g (.degree. C.)
T.sub.x (.degree. C.) .DELTA.T.sub.x (.degree. C.) T.sub.s
(.degree. C.) T.sub.l (.degree. C.) 24
Ni.sub.75.15Cr.sub.2.02Nb.sub.3.33P.sub.15.85Si.sub.0.48B.sub.3.17
395.0 427.1 32.1 834.0 893.1 26
Ni.sub.74.77Cr.sub.2.01Nb.sub.3.32P.sub.16.17Si.sub.0.49B.sub.3.24
392.5 428.6 36.1 831.9 899.1 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 399.8
436.5 36.7 832.5 898.6 29
Ni.sub.74.03Cr.sub.1.99Nb.sub.3.28P.sub.16.83Si.sub.0.51B.sub.3.36
401.5 445.1 43.6 834.6 893.5 30
Ni.sub.73.84Cr.sub.1.98Nb.sub.3.28P.sub.16.99Si.sub.0.51B.sub.3.4
400.8 446.9 46.1 832.3 898.3
[0124] Specific embodiments of metallic glasses formed of alloys
having compositions according to the formula
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3,
where w ranges from -2 to +3, are presented in Table 9. The
corresponding critical rod diameters and notch toughness values are
also listed in Table 9.
[0125] FIG. 13 provides a data plot showing the effect of varying
the Cr atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 on
the critical rod diameter of the alloys. The critical rod diameter
is shown to increase from 2 to 8 mm as the Cr concentration
increases from 0 to 2.5 atomic percent, remains constant at 8 mm as
the Cr concentration is in the range of 2.5 to about 4 atomic
percent, and then decreases slightly back to 7 mm as the Cr
concentration increases further to 5 atomic percent. The critical
rod diameter is at least 5 mm when the Cr content is at least 1
atomic percent.
[0126] FIG. 14 provides a data plot showing the effect of varying
the Cr atomic concentration at the expense of Ni according to the
formula
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 on
the notch toughness of the metallic glasses. The notch toughness is
shown to increase with decreasing Cr content, from 83.6 MPa
m.sup.1/2 for the alloy containing 5 atomic percent Cr to 103.7 MPa
m.sup.1/2 for the alloy containing 1.5 atomic percent Cr, and
slightly drops to 98.0 MPa m.sup.1/2 when the Cr content decreases
further to 1 atomic percent. The notch toughness is at least 96 MPa
m.sup.1/2 in the range where the Cr content is less than 2.5 atomic
percent, and is at least 100 MPa m.sup.1/2 when the Cr content is
not more than 2 atomic percent.
TABLE-US-00009 TABLE 9 Sample alloys demonstrating the effect of
increasing the Cr atomic concentration at the expense of Ni
according to the formula
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 on
the critical rod diameter and notch toughness of the sample
metallic glass formed of the sample alloys. Notch Critical Rod
Toughness Sample Composition Diameter [mm] K.sub.Q (MPa m.sup.1/2)
31 Ni.sub.76.4Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 2 -- 32
Ni.sub.75.4Cr.sub.1Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 5 98.0
.+-. 2.6 33
Ni.sub.74.9Cr.sub.15Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 6 103.7
.+-. 1.4 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 7 101.9
.+-. 4.4 34
Ni.sub.73.9Cr.sub.2.5Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 8 93.8
.+-. 3.2 35
Ni.sub.73.4Cr.sub.3Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 8 91.4
.+-. 4.6 36
Ni.sub.72.4Cr.sub.4Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 8 92.9
.+-. 2.0 37
Ni.sub.71.4Cr.sub.5Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 7 83.6
.+-. 4.1
[0127] FIG. 15 provides calorimetry scans for sample metallic
glasses
Ni.sub.74.4-wCr.sub.2+.sub.wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3
in accordance with embodiments of the disclosure. The glass
transition temperature T.sub.g, crystallization temperature
T.sub.x, solidus temperature T.sub.s, and liquidus temperature
T.sub.l are indicated by arrows in FIG. 15. Table 10 lists the
glass transition temperature T.sub.g, crystallization temperature
T.sub.x, solidus temperature T.sub.s, and liquidus temperature
T.sub.l along with the respective .DELTA.T.sub.x value for sample
metallic glasses
Ni.sub.74.4-wCr.sub.2+.sub.wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3
in accordance with embodiments of the disclosure.
[0128] As shown in Table 10, the .DELTA.T.sub.x value for the
Cr-free metallic glass is 33.2.degree. C., the value for the
metallic glass containing 1 atomic percent Cr (Sample 32) is
37.1.degree. C., the value for the metallic glass containing 2
atomic percent Cr (Sample 9) is 36.7.degree. C., the value for the
metallic glass containing 3 atomic percent Cr (Sample 35) is
38.1.degree. C., and the value for the metallic glass containing 4
atomic percent Cr (Sample 36) is 38.8.degree. C. For sample
metallic glasses where the atomic concentration of Cr is in the
range of 0.5 to 4 atomic percent, .DELTA.T.sub.x is at least
35.degree. C.
TABLE-US-00010 TABLE 10 Sample alloys demonstrating the effect of
increasing the Cr atomic concentration at the expense of Ni
according to the formula
Ni.sub.74.4-wCr.sub.2+wNb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 on
the glass transition temperature T.sub.g, crystallization
temperature T.sub.x, solidus temperature T.sub.s, liquidus
temperature T.sub.l and on .DELTA.T.sub.x (=T.sub.x - T.sub.g).
Sample Composition T.sub.g (.degree. C.) T.sub.x (.degree. C.)
.DELTA.T.sub.x (.degree. C.) T.sub.s (.degree. C.) T.sub.l
(.degree. C.) 31 Ni.sub.76.4Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3
399.5 432.7 33.2 837.6 892.5 32
Ni.sub.75.4Cr.sub.1Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 397.0
434.1 37.1 835.9 895.1 9
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 399.8
436.5 36.7 832.5 898.6 35
Ni.sub.73.4Cr.sub.3Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 404.1
442.2 38.1 833.4 908.8 36
Ni.sub.72.4Cr.sub.4Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3 401.7
440.5 38.8 832.1 898.3
[0129] FIG. 16 presents a compositional range plot in two
compositional directions, y and z, representing the contents of
(P,Si) and B respectively, when the contents of Cr, Nb, and Si are
held constant at 2 atomic percent, 3.3 atomic percent, and 0.5
atomic percent, respectively, according to equation
Ni.sub.94.7-y-zCr.sub.2Nb.sub.3.3P.sub.y-0.5Si.sub.0.5B.sub.z. The
solid line marks the compositional range disclosed in the
disclosure, while the dashed line marks the range disclosed in U.S.
patent application Ser. No. 13/592,095. The various symbols
represent plots of various sample alloys taken from Tables 5 and 7,
with the critical rod diameter of each alloy designated by the
symbol shape (see inset), and the notch toughness of the metallic
glass formed from each alloy (in MPa m.sup.1/2) given by the number
appearing over each symbol.
[0130] As seen in FIG. 16, when the contents of Cr, Nb, and Si are
held constant at 2 atomic percent, 3.3 atomic percent, and 0.5
atomic percent, respectively, the compositional range for (P,Si)
and B disclosed in the disclosure does not overlap with the
compositional range disclosed in U.S. patent application Ser. No.
13/592,095. In fact, the (P,Si) and B range disclosed in the
current disclosure does not overlap with that in U.S. patent
application Ser. No. 13/592,095 at any Cr, Nb, and Si content
within the presently disclosed ranges. FIG. 16 also reveals that
all example or sample alloys that are within the presently
disclosed range have a critical rod diameter of at least 5 mm and
the metallic glasses formed from the example alloys have a notch
toughness of at least 96 MPa m.sup.1/2, while all example alloys
that are in the range disclosed in U.S. patent application Ser. No.
13/592,095 have a critical rod diameter of at least 5 mm but the
metallic glasses formed from the example alloys have a notch
toughness of less than 96 MPa m.sup.1/2.
[0131] FIG. 17 illustrates a 7 mm rod of metallic glass
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3
processed by water quenching the high temperature melt in a fused
silica tube having a wall thickness of 0.5 mm. FIG. 18 illustrates
an X-ray diffractogram verifying the amorphous structure of a 7 mm
diameter rod of sample metallic glass
Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.16.5Si.sub.0.5B.sub.3.3
processed by water quenching the high temperature melt in a fused
silica tube having a wall thickness of 0.5 mm.
[0132] Description of Methods of Processing the Sample Alloys
[0133] The particular method for producing the alloy ingots
involves inductive melting of the appropriate amounts of elemental
constituents in a quartz tube under inert atmosphere. The purity
levels of the constituent elements were as follows: Ni 99.95%, Cr
99.8%, Nb 99.95%, P 99.999%, P 99.9999%, Si 99.9999%, and B 99.5%.
The melting crucible may alternatively be a ceramic such as alumina
or zirconia, graphite, sintered crystalline silica, or a
water-cooled hearth made of copper or silver.
[0134] The particular method for producing the rods of sample
metallic glasses from the alloy ingots involves re-melting the
alloy ingots in quartz tubes having 0.5 mm thick walls in a furnace
at 1350.degree. C. under high purity argon and rapidly quenching in
a room-temperature water bath. Alternatively, the bath could be ice
water or oil. Metallic glass articles could be alternatively formed
by injecting or pouring the molten alloy into a metal mold. The
mold could be made of copper, brass, or steel, among other
materials.
[0135] In some embodiments, prior to producing a metallic glass
article, the alloyed ingots could be fluxed with a reducing agent
by re-melting the ingots in a quartz tube under inert atmosphere,
bringing the alloy melt in contact with the molten reducing agent,
and allowing the two melts to interact for about 1000 s at a
temperature of about 1200.degree. C. or higher, and subsequently
water quenching. In one embodiment, the reducing agent is boron
oxide.
Test Methodology for Assessing Glass-Forming Ability
[0136] The glass-forming ability of each alloy was assessed by
determining the maximum rod diameter in which the amorphous phase
of the alloy (i.e. the metallic glass phase) could be formed when
processed by the methods described above. X-ray diffraction with
Cu-K.alpha. radiation was performed to verify the amorphous
structure of the alloys.
[0137] Test Methodology for Measuring Notch Toughness
[0138] The notch toughness of sample metallic glasses was performed
on 3-mm diameter rods. The rods were notched using a wire saw with
a root radius ranging from 0.10 to 0.13 mm to a depth of
approximately half the rod diameter. The notched specimens were
placed on a 3-point bending fixture with span of 12.7 mm, and
carefully aligned with the notched side facing downward. The
critical fracture load was measured by applying a monotonically
increasing load at constant cross-head speed of 0.001 mm/s using a
screw-driven testing frame. At least three tests were performed,
and the variance between tests is included in the notch toughness
plots. The stress intensity factor for the geometrical
configuration employed here was evaluated using the analysis by
Murakimi (Y. Murakami, Stress Intensity Factors Handbook, Vol. 2,
Oxford: Pergamon Press, p. 666 (1987)).
Test Methodology for Differential Scanning Calorimetry
[0139] Differential scanning calorimetry was performed on sample
metallic glasses at a scan rate of 20 K/min to determine the
glass-transition and crystallization temperatures of sample
metallic glasses formed from the glass-forming alloys, and also
determine solidus and liquidus temperatures of the alloys.
[0140] The combination of good glass-forming ability and high
toughness exhibited by the metallic glasses of the disclosure make
the present alloys and metallic glasses excellent candidates for
various engineering applications. Among many applications, the
disclosed alloys may be used in dental and medical implants and
instruments, luxury goods, and sporting goods applications.
[0141] The alloys and metallic glasses described herein can also be
valuable in the fabrication of electronic devices. An electronic
device herein can refer to any electronic device known in the art.
For example, it can be a telephone, such as a mobile phone, and a
land-line phone, or any communication device, such as a smart
phone, including, for example an iPhone.RTM., and an electronic
email sending/receiving device. It can be a part of a display, such
as a digital display, a TV monitor, an electronic-book reader, a
portable web-browser (e.g., iPad.RTM.), and a computer monitor. It
can also be an entertainment device, including a portable DVD
player, conventional DVD player, Blue-Ray disk player, video game
console, music player, such as a portable music player (e.g.,
iPod.RTM.), etc. It can also be a part of a device that provides
control, such as controlling the streaming of images, videos,
sounds (e.g., Apple TV.RTM.), or it can be a remote control for an
electronic device. It can be a part of a computer or its
accessories, such as the hard drive tower housing or casing, laptop
housing, laptop keyboard, laptop track pad, desktop keyboard,
mouse, and speaker. The article can also be applied to a device
such as a watch or a clock.
[0142] Having described several embodiments, it will be recognized
by those skilled in the art that various modifications, alternative
constructions, and equivalents may be used without departing from
the spirit of the disclosure. Those skilled in the art will
appreciate that the presently disclosed embodiments teach by way of
example and not by limitation. Therefore, the matter contained in
the above description or shown in the accompanying drawings should
be interpreted as illustrative and not in a limiting sense.
Additionally, a number of well-known processes and elements have
not been described in order to avoid unnecessarily obscuring the
disclosure.
[0143] The following claims are intended to cover all generic and
specific features described herein, as well as all statements of
the scope of the present method and system, which, as a matter of
language, might be said to fall therebetween.
* * * * *