Heat exchanger cast in metal matrix composite and method of making the same

• US 20030024120A1
• Filed: 08/16/2002
• Published: 02/06/2003
• Est. Priority Date: 11/27/2000
• Status: Active Grant

• Current Assignee: Kevin Fennessy, Mark Occhionero, Mark Rossi, Richard Adams
• Original Assignee: Kevin Fennessy, Mark Occhionero, Mark Rossi, Richard Adams
• Inventors: Rossi, Mark, Adams, Richard, Fennessy, Kevin, Occhionero, Mark
• Granted Patent: US 6,668,912 B2
• Time in Patent Office: Days
• US Class Current: 29/890.03
• CPC Class Codes: B22D 19/0072 for making objects with integrated channels
• CPC Class Codes: B22D 19/14 the objects being filamentary or particulate in form making alloys containing fibres or filaments by contacting the fibres or filaments with molten metal C22C47/08
• CPC Class Codes: C22C 1/1021 the preform being ceramic
• CPC Class Codes: C22C 1/1036 starting from a melt
• CPC Class Codes: F28F 13/00 Arrangements for modifying heat-transfer, e.g. increasing, decreasing F28F1/00 - F28F11/00 take precedence
• CPC Class Codes: H01L 21/4871 Bases, plates or heatsinks
• CPC Class Codes: H01L 23/3733 having a heterogeneous or anisotropic structure, e.g. powder or fibres in a matrix, wire mesh, porous structures H01L23/3732, H01L23/3737 take precedence
• CPC Class Codes: H01L 23/473 by flowing liquids H01L23/4332, H01L23/4338 take precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 29/4935 Heat exchanger or boiler making

Abstract

The specification and drawings describe and show an embodiment of and method of forming a liquid flow through heat exchanger structure cast in a metal matrix composite. The composite comprises a preform reinforcement material infiltrated with molten metal. The composite reinforcement material is injection molded around the heat exchanger structure allowing for intimate contact between the composite and structure. The composite formed has a specific coefficient of thermal expansion to match an active heat-generating device mounted thereon. The present invention allows for enhanced thermal and mechanical properties by eliminating voids or gaps at the composite to heat exchanger structure interface, these voids or gaps being present in prior art fabrication methods or induced by usage due to thermal cycling of prior art composites. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Claims

1. A method of forming a metal matrix composite comprising the steps of:

positioning an insert into a first mold chamber of a closed mold;

filling said first mold chamber with a preform reinforcement material such that the insert is completely encased within said preform reinforcement material, said reinforcement material in intimate contact with the surface of said insert;

positioning said completely encased insert into a second mold chamber of a closed mold;

infiltrating said second mold chamber with a molten metal such that said reinforcement material is infiltrated with said metal.

8. A method as described in claim 1, wherein the insert comprises a closed box structure with closed ends and including after the step of infiltrating said second mold chamber with a molten metal, the step of removing said metal matrix composite from said second mold chamber.

9. A method as described in claim 8, wherein said closed box structure contains baffles or pin fins integrated therein.

10. A method as described in claim 9, including after the step of removing said metal-matrix composite, the step of exposing the baffles or pin fins.

11. A method as defined in claim 1, including during the step of filling said first mold chamber with said preform reinforcement material, the step of chilling said first mold chamber.

12. A method as defined in claim 11, including after the chilling step, the step of removing said completely encased insert from said first mold chamber.

13. A method as defined in claim 12, including after the removing step, the step of drying said completely encased insert.

14. A method as defined in claim 13, including after the drying step, the step of backfilling said reinforcement material.

15. A method as defined in claim 14, including after the step of infiltrating said second mold chamber with a molten metal, the step of removing said metal matrix composite.

16. A method as defined in claim 15, including after the step of removing said metal matrix composite, the step of exposing said insert.

2. A method as described in claim 1, wherein said first mold chamber and said second mold chamber have a bottom portion and a top portion.

17. A system comprising:

an electronic component having a specific coefficient of thermal expansion; and

a metal matrix composite having a coefficient of thermal expansion substantially equal to that of said component, said composite having a shape conforming to said component such that heat can be transferred therebetween, said composite comprising an insert, said insert completely encased within a metal matrix composite, said insert having an inlet and outlet connected to a liquid source, said insert confining the flow of said liquid within said metal matrix composite.

17-1. A system for cooling high power, heat generating devices, comprising:

a heat generating device having a specific coefficient of thermal expansion;

a metal matrix composite having a coefficient of thermal expansion substantially equal to that of said heat generating device, said composite having a shape conforming to said heat generating device such that heat can be transferred therebetween, said composite comprising an insert, said insert completely encased within said metal matrix composite,

said insert having an inlet and outlet connected to a liquid source, said insert confining the flow of said liquid within said metal matrix composite, said composite further comprising a reinforcement material, said reinforcement material in intimate contact with the surface of said insert.

18. A metal matrix composite liquid flow through cooler for cooling high power, heat generating devices, comprising:

An insert, said insert having an inlet and outlet through which a cooling liquid flows;

a housing which encloses said insert, said housing cast from a metal-matrix composite material having a coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of said heat generating devices, said metal matrix composite containing a reinforcement material, said reinforcement material in intimate contact with the surface of said insert.

3. A method as described in claim 2, wherein said top portion of said first mold chamber has hold-downs affixed thereto.

4. A method as described in claim 3, wherein said bottom portion of said first mold chamber has cradles affixed thereto.

5. A method as described in claim 4, wherein said insert is placed between said cradles and said hold-downs in said first mold chamber of said closed mold.

6. A method as described in claim 1, wherein the insert comprises a hollow core with closed ends and including after the step of infiltrating said second mold chamber with a molten metal, the step of removing said metal matrix composite from said second mold chamber.

7. A method as described in claim 6, including after the step of removing said metal-matrix composite, the step of exposing the hollow core.

19. A liquid flow through cooler as defined in claim 18, wherein the coefficient of thermal expansion of the housing is between 6 and 13 ppm/degree Celsius.

20. A liquid flow through cooler as defined in claim 19, wherein an aluminum silicon-carbide composite material is used as the housing material, and wherein the housing is cast from said aluminum silicon-carbide composite material.

21. A liquid flow through cooler as defined in claim 18, wherein an aluminum silicon-carbide composite material is used as the housing material, and wherein the housing is cast from said aluminum silicon-carbide composite material.

22. A liquid flow through cooler as defined in claim 18, wherein said insert is a tube structure.

23. A liquid flow through cooler as defined in claim 18, wherein said insert is a closed box structure, said closed box structure containing baffles or pin fins.

24. A liquid flow through cooler as defined in claim 23, wherein said closed box structure contains baffles integrated therein.

25. A liquid flow through cooler as defined in claim 23, wherein said closed box structure contains pin fins integrated therein.

26. A liquid flow through cooler as defined in claim 20 wherein the conductivity of said aluminum silicon carbide is between the ranges of about 160 to about 200 W/(mk) at room temperature.

18-2. A metal matrix composite liquid flow through cooler for cooling high power, heat generating devices, comprising:

an insert, said insert having an inlet and outlet through which a cooling liquid flows;

a metal-matrix composite containing said insert, said metal-matrix composite material having a coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of the heat generating devices, said metal-matrix composite containing a reinforcement material, said reinforcement material in intimate contact with the surface of said insert.

19-3. A liquid flow through cooler as defined in claim 18, wherein the coefficient of thermal expansion of said metal-matrix composite is between about 4 to about 16 ppm/degree Celsius.

20-4. A liquid flow through cooler as defined in claim 18, wherein said metal matrix composite comprises aluminum silicon carbide.

22-5. A liquid flow through cooler as defined in claim 18, wherein said insert is a tube structure.

23-6. A liquid flow through cooler as defined in claim 18, wherein said insert is a closed box structure.