High Thermal Conductivity Heat Sinks With Z-Axis Inserts

Abstract

A heat sink including a composite material base plate that defines at least one through hole. At least one composite material insert is position into the at least one through hole prior to pressure infiltration. The composite material insert is oriented to increase thermal conductivity in the through-plan direction.

1 . A heat sink comprising:
 a) a composite material base plate that defines at least one through hole; and   b) at least one composite material insert that is position into the at least one through hole prior to pressure infiltration, wherein the composite material insert is oriented to increase thermal conductivity in a through-plane direction.   
   
   
       2 . The heat sink of  claim 1  wherein the composite material base plate comprises a graphite material. 
   
   
       3 . The heat sink of  claim 1  wherein the composite material comprises a natural graphite flake material. 
   
   
       4 . The heat sink of  claim 1  wherein the composite material comprises chips of pyrolitic graphite. 
   
   
       5 . The heat sink of  claim 1  wherein the at least one composite material insert is formed of substantially the same composite material that defines the at least one through hole. 
   
   
       6 . The heat sink of  claim 1  further comprising a skin material that is positioned over the heat sink prior to pressure infiltration 
   
   
       7 . The heat sink of  claim 6  wherein the skin material comprises at least one of silica scrim, felt, alumina felt, metal matrix composite material, and a thinly applied ceramic powder. 
   
   
       8 . The heat sink of  claim 1  wherein the at least one composite material insert is machined from natural graphite. 
   
   
       9 . The heat sink of  claim 1  wherein the composite material base plate comprises a metal matrix composite material. 
   
   
       10 . The heat sink of  claim 1  wherein the at least one composite material insert is mechanically restrained and cast into at least one of molten Al, Mg, and Cu. 
   
   
       11 . The heat sink of  claim 1  wherein the composite material base plate and the at least one composite material insert are infiltrated with an Al-Si alloy. 
   
   
       12 . The heat sink of  claim 1  wherein the composite material base plate and the at least one composite material insert are infiltrated with an Mg alloy. 
   
   
       13 . The heat sink of  claim 1  wherein the composite material base plate and the at least one composite material insert are infiltrated with a Cu alloy. 
   
   
       14 . The heat sink of  claim 1  wherein an average coefficient of thermal expansion of the at least one composite material insert is varied from 4 ppm/K to 12 ppm/K to provide an approximate coefficient of thermal expansion match. 
   
   
       15 . The heat sink of  claim 1  wherein the composite material base plates comprise at least one of AlSiCp, and a metal matrix composite material. 
   
   
       16 . The heat sink of  claim 1  wherein the composite material inserts are pre-positioned into a metal matrix composite material preforms prior to infiltration. 
   
   
       17 . The heat sink of  claim 1  wherein the composite material insert are formed using hexagonal mitering to provide high thermal conductivity in regions around the center about 60 degrees apart so as to approach high thermal conductivity in radial directions. 
   
   
       18 . The heat sink of  claim 1  wherein the at least one composite material insert is formed using natural flake graphite and the volume fraction of natural flake graphite is adjusted to provide a predetermined average coefficient of thermal expansion. 
   
   
       19 . The heat sink of  claim 1  wherein the at least one composite material insert is mitered to provide high thermal conductivity in the through-plane direction. 
   
   
       20 . The heat sink of  claim 1  wherein the at least one composite material insert is mitered to provide high orthogonal heat spreading. 
   
   
       21 . The heat sink of  claim 1  wherein the at least one composite material insert comprises highly oriented pyrolytic graphite material mitered so as to direct heat in both the through-plane direction and radially outward. 
   
   
       22 . A heat sink comprising:
 a) a base plate that defines at least one through hole; and   b) at least one composite material insert that is position into the at least one through hole prior to pressure infiltration, wherein the composite material insert is oriented to increase thermal conductivity in a through-plane direction.   
   
   
       23 . The heat sink of  claim 22  wherein the base plate comprises at least one of aluminum, copper and magnesium. 
   
   
       24 . The heat sink of  claim 22  wherein the composite material insert comprises at least one of aluminum graphite, copper graphite, and magnesium graphite. 
   
   
       25 . A heat sink comprising:
 a) a composite material base plate that defines at least one through hole;   b) at least one composite material insert that is position into the at least one through hole prior to pressure infiltration, wherein the composite material insert is oriented to increase thermal conductivity in a through-plane direction; and   c) at least one metal matrix composite material preform skin pad, wherein the metal matrix composite material comprising the preform skin pad is designed to achieve a predetermined local thermal expansion coefficient.   
   
   
       26 . The heat sink of  claim 25  wherein the composite material base plate comprises AlGr p . 
   
   
       27 . The heat sink of  claim 25  wherein the composite material base plate comprises MetGraf™. 
   
   
       28 . The heat sink of  claim 25  wherein the at least one metal matrix composite material preform skin pad is co-infiltrated with the at least one composite material insert. 
   
   
       29 . The heat sink of  claim 28  wherein the co-infiltration is performed with at least one of Al, Mg, and Cu matrix alloys.