BULK NICKEL-NIOBIUM-PHOSPHORUS-BORON GLASSES BEARING LOW FRACTIONS OF CHROMIUM AND EXHIBITING HIGH TOUGHNESS

Abstract

NiCrNbPB 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.

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.(95wxyz)Cr.sub.2+wNb.sub.3+x(P.sub.1aSi.sub.a).sub.yB.sub.zEq. (1) 1.5w<0.5; 0.5x1; 2.6z4; 20.2+0.2w0.65|x|zy20.8z; 0a0.1; 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 1w<0.5.

3. The alloy of claim 1, wherein 0.4x0.8.

4. The alloy of claim 1, wherein 2.8z3.8.

5. The alloy of claim 1, wherein 20.2+0.2w0.65|x|zy20.7z.

6. The alloy of claim 1, wherein 0a0.8.

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+0.2w0.65|x|z to 20.8z, 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

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.1aSi.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.1aSi.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.1aSi.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.74.7xCr.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.74.7xCr.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.74.7xCr.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.19.8zSi.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.19.8zSi.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.19.8zSi.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.100yz[P.sub.0.813Si.sub.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.100yz[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.100yz[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.

[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.74.4wCr.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.74.4wCr.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.74.4wCr.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.94.7yzCr.sub.2Nb.sub.3.3P.sub.y0.5Si.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 NiCrNbPB 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.2Eq. (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 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, T.sub.x=T.sub.xT.sub.g, measured at heating rate of 20 K/min. A large 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, NiCrNbPB 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] NiCrNbPB 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.(95wxyz)Cr.sub.2+wNb.sub.3+x(P.sub.1aSi.sub.a).sub.yB.sub.zEq. (1) [0097] 1.5w0.5; [0098] 0.5x1; [0099] 2.6z4; [0100] 20.2+0.2w0.65|x|zy20.8z; [0101] 0a0.1; [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.1aSi.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.1aSi.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.1aSi.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.1aSi.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.1aSi.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.1aSi.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 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 C., while the value for the metallic glass containing 0.25 atomic percent Si (Sample 2) is 35.8 C. and the value for the metallic glass containing 0.5 atomic percent Si (Sample 2) is 37.3 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 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 C. For sample metallic glasses where the Si concentration is up to 1, T.sub.x is at least 35 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.1aSi.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 T.sub.x (=T.sub.x T.sub.g). Sample Composition T.sub.g ( C.) T.sub.x ( C.) T.sub.x ( C.) T.sub.s ( C.) T.sub.l ( 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.74.7xCr.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.74.7xCr.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.74.7xCr.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.74.7xCr.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.74.7xCr.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 T.sub.x value for sample metallic glasses Ni.sub.74.7xCr.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 C., and the value for the metallic glass containing 3.7 atomic percent Nb (Sample 11) is 40.5 C. The value for the metallic glass containing 4.1 atomic percent Nb (Sample 13) is 34.0 C., and the value for the metallic glass containing 4.5 atomic percent Nb (Sample 14) is 30.5 C. For sample metallic glasses where the Nb concentration is equal to or less than 4 atomic percent, T.sub.x is at least 35 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 T.sub.x (=T.sub.x T.sub.g). Sample Composition T.sub.g ( C.) T.sub.x ( C.) T.sub.x ( C.) T.sub.s ( C.) T.sub.l ( 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.19.8zSi.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.19.8zSi.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.19.8zSi.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.19.8zSi.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.19.8zSi.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 T.sub.x value for sample metallic glasses Ni.sub.74.4Cr.sub.2Nb.sub.3.3P.sub.19.8zSi.sub.0.5B.sub.z in accordance with embodiments of the disclosure.

[0118] As shown in Table 6, T.sub.x values are larger when the B concentration exceeds 3.3 atomic percent compared to the 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 C., and the value for the metallic glass containing 2.9 atomic percent B (Sample 17) is 35.9 C., and the value for the metallic glass containing 3.3 atomic percent B (Sample 9) is 36.7 C. However, the value for the metallic glass containing 3.7 atomic percent B (Sample 20) is 41.2 C., and the value for the metallic glass containing 4.3 atomic percent B (Sample 23) is 41.9 C. For sample metallic glasses where the B concentration is in the range of 2.5 to 4 atomic percent, T.sub.x is at least 35 C., while those where the B concentration is in is greater than 3.3 atomic percent, T.sub.x is at least 40 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.19.8zSi.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 T.sub.x (=T.sub.x T.sub.g). Sample Composition T.sub.g ( C.) T.sub.x ( C.) T.sub.x ( C.) T.sub.s ( C.) T.sub.l ( 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.100yz[P.sub.0.813Si.sub.0.025B.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.100yz[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.100yz[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.100yz[P.sub.0.813Si.sub.0.025B.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.100yz[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 T.sub.x value for sample metallic glasses [Ni.sub.0.933Cr.sub.0.025Nb.sub.0.042].sub.100yz[P.sub.0.813Si.sub.0.025B.sub.0.162].sub.y+z in accordance with embodiments of the disclosure.

[0123] As shown in Table 8, 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 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 C. and 36.7 C., while the values for the metallic glasses containing 20.7 to 20.9 atomic percent metalloids (Samples 29, 30) is between 43.6 C. and 46.1 C. For sample metallic glasses where the metalloid concentration is greater than 20.5 atomic, T.sub.x is at least 40 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.100yz[P.sub.0.813Si.sub.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 T.sub.x (=T.sub.x T.sub.g). Sample Composition T.sub.g ( C.) T.sub.x ( C.) T.sub.x ( C.) T.sub.s ( C.) T.sub.l ( 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.74.4wCr.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.74.4wCr.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.74.4wCr.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.74.4wCr.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.74.4wCr.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 T.sub.x value for sample metallic glasses Ni.sub.74.4wCr.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 T.sub.x value for the Cr-free metallic glass is 33.2 C., the value for the metallic glass containing 1 atomic percent Cr (Sample 32) is 37.1 C., the value for the metallic glass containing 2 atomic percent Cr (Sample 9) is 36.7 C., the value for the metallic glass containing 3 atomic percent Cr (Sample 35) is 38.1 C., and the value for the metallic glass containing 4 atomic percent Cr (Sample 36) is 38.8 C. For sample metallic glasses where the atomic concentration of Cr is in the range of 0.5 to 4 atomic percent, T.sub.x is at least 35 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.74.4wCr.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 T.sub.x (=T.sub.x T.sub.g). Sample Composition T.sub.g ( C.) T.sub.x ( C.) T.sub.x ( C.) T.sub.s ( C.) T.sub.l ( 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.94.7yzCr.sub.2Nb.sub.3.3P.sub.y0.5Si.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 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 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 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, 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), 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), 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), 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.