Amorphous steel composites with enhanced strengths, elastic properties and ductilities

Patent metadata

Field	Value
Publication number	US-9555467-B2
Application number	US-201514714826-A
Country	US
Kind code	B2
Filing date	May 18, 2015
Priority date	Feb 24, 2005
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

Amorphous steel composites with enhanced mechanical properties and related methods for toughening amorphous steel alloys. The composites are formed from monolithic amorphous steel and hard ceramic particulates, which must be embedded in the glass matrix through melting at a temperature above the melting point for the steel but below the melting point for the ceramic. The ceramics may be carbides, nitrides, borides, iron-refractory carbides, or iron-refractory borides. The produced composites may be one of two types, primarily distinguished by the methods for embedding the ceramic particulates in the steel. These methods may be applied to a variety of amorphous steels as well as other non-ferrous amorphous metals, and the resulting composites can be used in various applications and utilizations.

First claim

We claim:

1. A method for enhancing the toughness of amorphous steel alloy that comprises:
a) milling carbide or nitride ceramic particulates to obtain a desired particle size distribution;
b) mixing the milled particles with ingots of monolithic amorphous steel alloy;
c) compacting the mixture to form a pellet; and
c) melting the pellet at a temperature above the melting point for the steel but below the melting point for the ceramic to form a composite ingot.

2. The method of claim 1 further comprising:
a) preparing ingots of monolithic amorphous steel alloy; and
b) casting the resulting ingot to form an amorphous steel composite.

3. The method of claim 2 , wherein the composite produced is the amorphous steel composite comprising a composition represented by the formula:
[Fe 1−a−b−c−d−e−f Mn a Cr b Mo c (Ln 1−x Y x ) d C e B f ] 100−α [CER] α
wherein Ln represents an element in the Lanthanide series such as Sm, Gd, Dy, Er, Yb, or Lu; and
wherein CER represents a ceramic consisting of one of three types:
i) a carbide or nitride comprised substantially of a composition represented by the formula:
M 0.5−y M′ y C 0.5−z N z

wherein M and M′ represent one or two group IV or V refractory metals such as Ti, Zr, Hf, V, Nb, or Ta, and
wherein y and z satisfy the relations 0.5≧y≧0 and 0.5.z≧0; or

ii) an iron-refractory carbide comprised substantially of a composition represented by the formula:
Fe 1−y−z M y C z
wherein M represents a refractory or reactive metal, and
wherein y and z satisfy the relations 1.0≧y≧0 and 1.0≧z≧0; or

iii) an iron-refractory boride comprised substantially of a composition represented by the formula:
Fe 1−y−z M y B z

wherein M represents a refractory or reactive metal, and
wherein y and z satisfy the relations 1.0≧y≧0 and 1.0≧z≧0; and

wherein a, b, c, d, e, f, x, and α satisfy the relations:
0.12≧a≧0, 0.18≧b≧0, 0.18≧c≧0.05, 0.03≧d>0, 0.18≧e≧0.12, 0.1≧f≧0.05, 1.0≧x≧0, 12≧α>0, c+d≦0.19, e+f≦0.25, and a+b+c+d+e+f≦0.55.

4. The method of claim 3 , wherein the partial composite of
[Fe 1−a−b−c−d−e−f Mn a Cr b Mo c (Ln 1−x Y x ) d C e B f ] 100−α further comprises elements X and/or Z, wherein:
X represents at least one transitional element, and
Z represents at least one Group B element.

5. The method of claim 2 , wherein the amorphous steel composite produced is at least about 0.1 mm in thickness in its minimum dimension.

6. The method of claim 2 , wherein the amorphous steel composite produced has a fracture yield strength of at least about 4.0 GPa.

7. The method of claim 2 , wherein the amorphous steel composite produced has a Young's modulus of at least about 220 GPa.

8. The method of claim 2 , wherein the amorphous steel composite produced has a bulk modulus of at least about 205 GPa.

9. The method of claim 2 , wherein the amorphous steel composite produced has a shear modulus of at least about 85 GPa.

10. The method of claim 2 , wherein the amorphous steel composite produced has a Poisson ratio of at least about 0.32.

11. A method for enhancing the toughness of amorphous steel alloy that comprises:
a) combining monolithic amorphous steel with Carbon, Boron, or Nitrogen to form a master alloy ingot;
b) melting the master alloy ingot at a temperature above the melting point for the steel but below the melting point for the ceramic;
c) mixing a group IV or V refractory metal in the melt to form ceramic particulates within the composite ingot; and
d) repeating the process as necessary to achieve the desired particle size and ceramic content.

12. The method of claim 11 further comprising:
a) preparing ingots of monolithic amorphous steel alloy; and
b) casting the resulting ingot to form an amorphous steel composite.

13. The method of claim 12 , wherein the composite produced is the amorphous steel composite comprising a composition represented by the formula:
[Fe 1−a−b−c−d−e−f Mn a Cr b Mo c (Ln 1−x Y x ) d C e B f ] 100−α [CER] α
wherein Ln represents an element in the Lanthanide series such as Sm, Gd, Dy, Er, Yb, or Lu; and
wherein CER represents a ceramic consisting of one of three types:
i) a carbide or nitride comprised substantially of a composition represented by the formula:
M 0.5−y M′ y C 0.5−z N z

wherein M and M′ represent one or two group IV or V refractory metals such as Ti, Zr, Hf, V, Nb, or Ta, and
wherein y and z satisfy the relations 0.5≧y≧0 and 0.5.z≧0; or

ii) an iron-refractory carbide comprised substantially of a composition represented by the formula:
Fe 1−y−z M y C z
wherein M represents a refractory or reactive metal, and
wherein y and z satisfy the relations 1.0≧y≧0 and 1.0≧z≧0; or

iii) an iron-refractory boride comprised substantially of a composition represented by the formula:
Fe 1−y−z M y B z

wherein M represents a refractory or reactive metal, and
wherein y and z satisfy the relations 1.0≧y≧0 and 1.0≧z≧0; and

wherein a, b, c, d, e, f, x, andα satisfy the relations:
0.12≧a≧0, 0.18≧b≧0, 0.18≧c≧0.05, 0.03≧d>0, 0.18≧e≧0.12, 0.1≧f≧0.05, 1.0≧x≧0, 12≧α>0, c+d≦0.19, e+f≦0.25, and a+b+c+d+e+f≦0.55.

14. The method of claim 13 , wherein the partial composite of
[Fe 1−a−b−c−d−e−f Mn a Cr b Mo c (Ln 1−x Y x ) d C e B f ] 100−α further comprises elements X and/or Z, wherein:
X represents at least one transitional element, and
Z represents at least one Group B element.

15. The method of claim 12 , wherein the amorphous steel composite produced is at least about 0.1 mm in thickness in its minimum dimension.

16. The method of claim 12 , wherein the amorphous steel composite produced has a fracture yield strength of at least about 4.0 GPa.

17. The method of claim 12 , wherein the amorphous steel composite produced has a Young's modulus of at least about 220 GPa.

18. The method of claim 12 , wherein the amorphous steel composite produced has a bulk modulus of at least about 205 GPa.

19. The method of claim 12 , wherein the amorphous steel composite produced has a shear modulus of at least about 85 GPa.

20. The method of claim 12 , wherein the amorphous steel composite produced has a Poisson ratio of at least about 0.32.

21. A method for enhancing the toughness of amorphous steel alloy that comprises:
a) milling ceramic particulates to obtain a desired particle size distribution;
b) mixing the ceramic particulates with ingots of monolithic amorphous steel alloy;
c) melting the mixture at a temperature above the melting point for the steel but below the melting point for the ceramic; and
d) precipitating the ceramic particulates from the mixture as it cools into a composite ingot.

22. The method of claim 21 further comprising:
a) preparing ingots of monolithic amorphous steel alloy; and
b) casting the resulting ingot to form an amorphous steel composite.

23. The method of claim 22 , wherein the composite produced is the amorphous steel composite comprising a composition represented by the formula:
[Fe 1−a−b−c−d−e−f Mn a Cr b Mo c (Ln 1−x Y x ) d C e B f ] 100−α [CER] α
wherein Ln represents an element in the Lanthanide series such as Sm, Gd, Dy, Er, Yb, or Lu; and
wherein CER represents a ceramic consisting of one of three types:
i) a carbide or nitride comprised substantially of a composition represented by the formula:
M 0.5−y M′ y C 0.5−z N z

wherein M and M′ represent one or two group IV or V refractory metals such as Ti, Zr, Hf, V, Nb, or Ta, and
wherein y and z satis

Assignees

• Univ Virginia Patent Foundation

Inventors

• Poon S Joseph
• Shiflet Gary J
• Gu Xiao-Jun

Classifications

• B22D7/00 Primary

  Casting ingots, {e.g. from ferrous metals}(equipment for conveying molten metal B22D35/00) · CPC title

• C22C33/0228

  comprising other non-metallic compounds or more than 5% of graphite · CPC title

• C22C35/005

  based on iron, e.g. ferro-alloys · CPC title

• C22C45/02

  with iron as the major constituent · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title