Metal composite article and method of manufacturing

• US 20090042057A1
• Filed: 08/11/2008
• Published: 02/12/2009
• Est. Priority Date: 08/10/2007
• Status: Abandoned Application

• Current Assignee: Springfield Munitions Company LLC
• Original Assignee: Springfield Munitions Company LLC
• Inventors: Smith, Timothy George, Thomas, Julian Alex
• Application Number:
  US12/228,231
• Publication Number:
  US 20090042057A1
• Time in Patent Office: Days
• US Class Current: 428/665
• CPC Class Codes: A01K 95/005 Sinkers not containing lead
• CPC Class Codes: B22F 1/09 Mixtures of metallic powders
• CPC Class Codes: B22F 1/108 Mixtures obtained by warm mixing
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/1035 Liquid phase sintering
• CPC Class Codes: B22F 3/225 by injection molding
• CPC Class Codes: B32B 15/01 all layers being exclusively metallic making layered metal workpieces by pressure cladding B23K20/22; making coatings with a metallic material characterised by its composition C23C30/00
• CPC Class Codes: C22C 1/045 Alloys based on refractory metals
• CPC Class Codes: F42B 12/74 of the core or solid body
• CPC Class Codes: F42B 7/046 Pellets or shot therefor
• CPC Class Codes: Y10T 428/1284 W-base component

Abstract

A composite metal article includes a higher melting point metal, a lower melting point alloy and at least one other metal with an intermediate melting point between that of the higher melting point metal and the lower melting point alloy. The at least one other metal is selected to aid in sinter-densification of the higher melting point metal in a temperature range above the liquidus temperature of the lower melting point alloy and below the melting point of the at least one other metal.

Claims

1. A composite metal article comprising:

a higher melting point metal;

a lower melting point alloy; and

at least one other metal with an intermediate melting point between that of the higher melting point metal and the lower melting point alloy,

wherein the at least one other metal is selected to aid in sinter-densification of the higher melting point metal in a temperature range above the liquidus temperature of the lower melting point alloy and below the melting point of the at least one other metal.

2. The composite metal article of claim 1, wherein the higher melting point metal is tungsten.

3. The composite metal article of claim 1, wherein the lower melting point alloy is bronze.

4. The composite metal article of claim 3, wherein the lower melting point alloy has a melting point lower than its base metal and higher than its alloying metal.

5. The composite metal article of claim 4, wherein the base metal of the lower melting point alloy is soluble in or is a solvent for the at least one other metal with an intermediate melting point.

6. The composite metal article of claim 4, wherein the base metal is copper and the alloying metal is tin.

7. The composite metal article of claim 1, wherein the at least one other metal is at least one of the following:

iron, nickel or any combination thereof.

8. The composite metal article of claim 1, wherein the at least one other metal has a degree of solubility in the lower melting point alloy once the lower melting point alloy has been substantially melted.

9. The composite metal article of claim 1, wherein at least a portion of the at least one other metal remains out of solution of the melted lower melting point alloy once the lower melting point alloy has been substantially melted.

10. The composite metal article of claim 1, wherein the at least one other metal substantially dissolves into the lower melting point alloy once it has been melted at an outer liquid boundary thereof, resulting in densification of the higher melting point metal due to a concentrated boundary layer of the at least one other metal in the melted lower melting point alloy.

11. The composite metal article of claim 1, wherein the at least one other metal is fully dissolved and redistributed at an atomic level throughout the lower melting point alloy.

12. The composite metal article of claim 1, wherein the density of the higher melting point metal is greater than the density of the lower melting point alloy and the at least one other metal.

13. A projectile at least partially formed from the composite metal article of claim 1.

14. A method of manufacturing a composite metal article, comprising:

mixing a higher melting point metal, a lower melting point alloy and at least one other metal with an intermediate melting point between that of the higher melting point metal and the lower melting point alloy to create a mixture;

combining the mixture with at least one of a wax binder and a polymer binder to create a resulting mixture and heating the resulting mixture to a temperature such that the at least one wax binder and polymer binder melts;

injection molding the heated mixture to form an article; and

sintering the article, wherein the higher melting point metal undergoes particle rearrangement due to a presence of the melted lower melting point alloy and simultaneous solid-state sinter-densification.

15. The method of claim 14, wherein the article is a projectile.

16. The method of claim 14, wherein the higher melting point metal is tungsten.

17. The method of claim 14, wherein the lower melting point alloy is bronze.

18. The method of claim 17, wherein the lower melting point alloy has a melting point lower than its base metal and higher than its alloying metal.

19. The method of claim 18, wherein the base metal of the lower melting point alloy is soluble in or is a solvent for the at least one other metal with an intermediate melting point.

20. The method of claim 18, wherein the base metal is copper and the alloying metal is tin.

21. The method of claim 14, wherein the at least one other metal is at least one of the following:

iron, nickel or any combination thereof.

22. The method of claim 14, wherein the at least one other metal has a degree of solubility in the lower melting point alloy once the lower melting point alloy has been substantially melted.

23. The method of claim 14, wherein at least a portion of the at least one other metal remains out of solution of the melted lower melting point alloy once the lower melting point alloy has been substantially melted.

24. The method of claim 14, wherein the at least one other metal dissolves into the lower melting point alloy once it has been melted at an outer liquid boundary thereof, resulting in densification of the higher melting point metal due to a concentrated boundary layer of the at least one other metal in the melted lower melting point alloy.

25. The method of claim 14, wherein the at least one other metal is fully dissolved and redistributed at an atomic level throughout the lower melting point alloy.

26. A projectile, comprising:

a mixture of a higher melting point metal, a lower melting point alloy and at least one other metal with an intermediate melting point between that of the higher melting point metal and the lower melting point alloy,

wherein the at least one other metal is selected to aid in sinter-densification of the higher melting point metal in a temperature range above the liquidus temperature of the lower melting point alloy and below the melting point of the at least one other metal.