Manufacturing method for aluminum matrix nanocomposite

• US 7,297,310 B1
• Filed: 12/16/2003
• Issued: 11/20/2007
• Est. Priority Date: 12/16/2003
• Status: Active Grant

• Current Assignee: YCT Industries, Ltd.
• Original Assignee: DWA Technologies, Inc.
• Inventors: Peng, Jack Y., Harrigan, William C. Jr., van den Bergh, Mark
• Primary Examiner(s): Wyszomierski; George
• Application Number:
  US10/738,275
• Time in Patent Office: 1,435 Days
• Field of Search: 419/38, 419/19
• US Class Current: 419/19
• CPC Class Codes: B22F 2009/0844 in controlled atmosphere
• CPC Class Codes: B22F 2202/13 Use of plasma
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/02 Compacting only
• CPC Class Codes: B22F 3/04 by applying fluid pressure , e.g. by cold isostatic pressing [CIP]
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: B22F 3/14 simultaneously
• CPC Class Codes: B22F 9/04 starting from solid material, e.g. by crushing, grinding or milling C22C1/1084 takes precedence; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C
• CPC Class Codes: B22F 9/08 by casting, e.g. through sieves or in water, by atomising or spraying using electric discharge B22F9/14
• CPC Class Codes: C22C 1/1084 by mechanical alloying (blending, milling)
• CPC Class Codes: C22C 1/1094 comprising an after-treatment
• CPC Class Codes: C22C 32/0036 Matrix based on Al, Mg, Be or alloys thereof

Abstract

A simple method to produce Aluminum Metal Matrix Nanocomposite with 2 to 35 volume percent of nano Al₂O₃ reinforcement phase without adding nano Al₂O₃ particles in a direct step of the metal matrix. The initial necessary material is an aluminum powder with nanoscale surface oxide. The volume percent of Al₂O₃ is determined by the particle size distribution and the thickness of the Al₂O₃ layer. The Al₂O₃ surface layers or shells are broken up and are uniformly distributed throughout the nanocomposite after the powder consolidation into billet and the hot and/or cold metal working of the billet.

Claims

1. A method of producing a nanocomposite, comprising the steps of:

a. producing a metal powder of spherical particles with nano surface metal oxides comprised of a metal inside of said particles and a metal oxide layer on the outside of said particles of said metal powder, wherein said metal oxide layer of said spherical particles is quantitatively controlled from a volume percent of nano phase metal oxides needed in said particles, which is defined by a symbol N_M and is specified by;

N_M=1−

(1−

2 T/D)³,

 

where T is a thickness of the metal oxide layer, and D is an average size of said particles;

b. producing a powder mixture comprising a metal alloy element powder of particles and said metal powder of spherical particles with nano surface metal oxides;

c. having consolidating performed to said powder mixture first to form a compacted mixture comprising a metal alloy powder of spherical particles with nano surface metal oxides having said metal alloy inside of said particles and a metal oxide layer on the outside of said particles of said metal alloy powder, wherein said metal alloy powder is formed from combining said metal powder with said metal alloy element powder;

said consolidating subsequently performed to said compacted mixture to form a composite billet; and

d. having a metal working performed to said composite billet to form said nanocomposite, wherein said outside layer of the metal oxides of said metal alloy powder of spherical particles is broken in the processes of making said nanocomposite, and breaking of said metal oxide layer happens during said consolidation step and subsequent metal working step, and broken metal oxide layer is uniformly distributed in a metal matrix resulting in a homogenous nanocomposite.

2. The method in accordance with claim 1, wherein said nanocomposite comprises about 2 to about 45 volume percentage of metal oxides of said broken metal oxide layer.

3. The method in accordance with claim 1, wherein said nanocomposite comprises about 55 to 98 volume percentage of said metal alloy.

4. The method in accordance with claim 1, wherein said metal powder of spherical particles with nano surface metal oxides comprises said particles having a structure of a metal core and a metal oxide ceramic shell.

5. The method in accordance with claim 4, wherein said metal core is an unalloyed aluminum core.

6. The method in accordance with claim 4, wherein said metal oxide ceramic shell is an aluminum oxide shell.

7. The method in accordance with claim 4, wherein said metal oxide ceramic shell has a thickness from about 2 nanometers to about 3 micrometers.

8. The method in accordance with claim 1, wherein said metal powder of spherical particles with nano surface metal oxides has an average particle diameter from about 20 nanometers to about 50 micrometers.

9. The method in accordance with claim 1, step. b, wherein said metal alloy element powder is selected from the group consisting of magnesium, copper, iron, zinc, nickel, magnesium, cobalt, silicon, titanium, alloys and combinations thereof.

10. The method in accordance with claim 1, wherein said step “

c”

further comprises the steps of;

a. compacting said powder mixture in a billet tool to form a compacted mixture having a density of about 50% to about 95% of theoretical density;

b. heating said compacted mixture in a controlled environment at a degassing temperature which is less than a lowest eutectic melt temperature of said compacted mixture;

c. degassing said compacted mixture at said degassing temperature for at least about one-half hour to form a degassed compact mixture;

d. heating said degassed compacted mixture to a consolidation temperature to form a preheated degassed compacted mixture; and

c. hot-pressing said preheated degassed compacted mixture to form said composite billet having a full density.

11. The method in accordance with claim 10, wherein said controlled environment is a vacuum environment.

12. The method in accordance with claim 10, wherein said controlled environment is an inert-gas environment.

13. The method in accordance with claim 10, wherein said controlled environment is an air environment.

14. The method in accordance with claim 10, wherein said consolidation temperature is a highest eutectic melt temperature of said compacted mixture.

15. The method in accordance with claim 10, wherein said consolidation temperature for said powder mixture is below the melt temperature of said metal alloy powder.

16. The method in accordance with claim 10, wherein said step “

c”

further comprises the steps of;

a. compacting said powder mixture to form said compacted mixture having a density of between about 85% and about 95% of theoretical density;

b. degassing said compacted mixture in said controlled environment at said degassing temperature;

c. degassing said compacted mixture at said degassing temperature for at least about one-half hour to form said degassed compacted mixture;

d. heating said degassed compacted mixture to a sintering temperature to form said composite billet having said density of between about 85% and about 95% theoretical density, wherein said sintering temperature is said highest eutectic melt temperature of said compacted mixture; and

e. hot-pressing said preheated degassed compacted mixture to form said composite billet having said full density.

17. The method in accordance with claim 10, wherein said step “

c”

further comprises the steps of;

a. compacting said powder mixture to form said compacted mixture having said density between about 50% to about 95% of theoretical density;

b. heating said compacted mixture in said controlled environment to said consolidation temperature to form a preheated compacted mixture; and

c. hot-pressing said preheated degassed compacted mixture to form said composite billet having said full density.

18. The method in accordance with claim 1, step d, wherein said metal working is a cold metal working selected from the group consisting of cold extrusion, cold forging, cold rolling and combinations thereof.

19. The method in accordance with claim 1, step. d, wherein said metal working is a hot metal working selected from the group consisting of hot extrusion, hot forging, hot rolling and combinations thereof at a temperature below said consolidation temperature.

20. The method in accordance with claim 1, step. d, wherein said metal working is a die casting.

21. The method in accordance with claim 1, wherein said metal working is a combination of cold metal working, hot metal working and die casting.

22. A method of producing a nanocomposite, comprising the steps of:

a. producing an aluminum alloy powder of spherical particles with nano surface aluminum oxides, comprised of said aluminum alloy inside of said spherical particles and an aluminum oxide layer on the outside of said spherical particles of said aluminum alloy powder, wherein said aluminum oxide layer of said spherical particles is quantitatively controlled from a volume percent of nano phase aluminum oxides needed in said particles, which is defined by a symbol N_A1 and is specified by;

N_A1=1−

(1−

2 T/D)³,

 

where T is a thickness of the aluminum oxide layer, and D is an average size of said particles;

b. having a consolidating performed to said aluminum alloy powder of spherical particles to form a compacted powder form;

said consolidating subsequently performed to said compacted powder from to form a composite billet; and

c. having a metal working performed to said composite billet to form said nanocomposite, wherein said outside layer of aluminum oxides of said aluminum alloy powder of spherical particles is broken in the processes of making said nanocomposite, and breaking of said aluminum oxide layer happens during said consolidation step and subsequent said metal working step, and broken aluminum oxide layer is uniformly distributed resulting in a homogenous nanocomposite.

23. The method in accordance with claim 22, wherein said nanocomposite comprises about 2 to about 45 volume percentage of aluminum oxides from said broken aluminum oxide layer.

24. The method in accordance with claim 22, wherein said nanocomposite comprises about 55 to 98 volume percentage of said aluminum alloy.

25. The method in accordance with claim 22, wherein said aluminum alloy powder of spherical particles with nano surface aluminum oxides comprises said particles having a structure of an aluminum alloy core and an aluminum oxide ceramic shell.

26. The method in accordance with claim 22, wherein said aluminum alloy powder of spherical particles with nano surface aluminum oxides has an average particle diameter from about 20 nanometers to about 50 micrometers.

27. The method in accordance with claim 25, wherein said aluminum oxide ceramic shell has a thickness from about 2 nanometers to about 3 micrometers.

28. The method in accordance with claim 22, step. a, wherein said aluminum alloy includes a metal from the group consisting of magnesium, copper, iron, zinc, nickel, manganese, cobalt, silicon, titanium, and combinations thereof.

29. The method in accordance with claim 22, wherein said step “

b”

further comprises the steps of;

a. compacting said aluminum alloy powder in a billet tool to form said compacted powder form having a density of about 50% to about 95% of theoretical density;

b. heating said compacted powder form in a controlled environment at a degassing temperature which is less than a lowest eutectic melt temperature of said aluminum alloy powder;

degassing said compacted powder form at said degassing temperature for at least about one-half hour to form a degassed compacted powder form;

d. heating said degassed compacted powder form to a consolidation temperature to form a preheated degassed compacted powder form; and

e. hot-pressing said preheated degassed compacted mixture to form said composite billet having a full density.

30. The method in accordance with claim 29, wherein said controlled environment is a vacuum environment.

31. The method in accordance with claim 29, wherein said controlled environment is an inert-gas environment.

32. The method in accordance with claim 29, wherein said controlled environment is an air environment.

33. The method in accordance with claim 29, wherein said step “

b”

further comprises the steps of;

a. compacting said aluminum alloy powder to form said compacted powder form having a density of between about 85% and about 95% of theoretical density;

b. heating said compacted powder form in said controlled environment at a degassing temperature which is less than a eutectic melt temperature of said aluminum alloy powder;

c. degassing said compacted powder form at said degassing temperature for at least about one-half hour to form said degassed compacted power form;

d. heating said degassed compacted powder form to a sintering temperature to form said composite billet having said density between about 85% and about 95% of theoretical density, wherein said sintering temperature is a highest eutectic melt temperature of said aluminum alloy powder; and

e. hot-pressing said preheated degassed compacted powder form to form said composite billet having said full density.

34. The method in accordance with claim 29, wherein said step “

b”

further comprises the steps of;

a. compacting said aluminum alloy powder to form said compacted powder form having said density between about 50% to about 95% of theoretical density;

b. heating said compacted powder form in said controlled environment to said consolidation temperature to form a preheated compacted powder form; and

c. hot-pressing said preheated compacted mixture to form said composite billet having said full density.

35. The method in accordance with claim 22, step. c, wherein said metal working is a cold metal working selected from the group consisting of cold extrusion, cold forging, cold rolling and combinations thereof.

36. The method in accordance with claim 22, step. c, wherein said metal working is a hot metal working selected from the group consisting of hot extrusion, hot forging, hot rolling and combinations thereof at a temperature below said consolidation temperature.

37. The method in accordance with claim 22, step. c, wherein said metal working is a die casting.

38. The method in accordance with claim 22, step. c, wherein said metal working is a combination of cold metal working, hot metal working and die casting.