Isotropic zero CTE reinforced composite materials

Abstract

A reinforced composite material, having isotropic thermal expansion properties and a low coefficient of thermal expansion over at least the temperature range of from about 0° C. to at least about 150° C. The composite material comprises in combination a preformed bonded powder material reinforcement in which the bonded powder material is chosen from zirconium tungstate, hafnium tungstate, zirconium hafnium tungstate, and mixtures of zirconium tungstate and hafnium tungstate, and a matrix material chosen from aluminium, aluminium alloys in which aluminium is the major component, magnesium, magnesium alloys in which magnesium is the major component, titanium, titanium alloys in which titanium is the major component, engineering thermoplastics and engineering thermoplastics containing a conventional solid filler.

1 . A reinforced composite material, having isotropic thermal expansion properties and a low coefficient of thermal expansion over at least the temperature range of from about 0° C. to at least about 150° C., which composite material comprises in combination a preformed bonded powder material reinforcement in which the bonded powder material is chosen from the group consisting of zirconium tungstate, hafnium tungstate, zirconium hafnium tungstate, and mixtures of zirconium tungstate and hafnium tungstate, and a matrix material chosen from the group consisting of aluminium, aluminium alloys in which aluminium is the major component, magnesium, magnesium alloys in which magnesium is the major component, titanium, titanium alloys in which titanium is the major component, engineering thermoplastics and engineering thermoplastics containing a conventional solid filler.  
     
     
         2 . A composite material according to  claim 1  wherein the bonding agent in the preformed bonded powder material reinforcement is silica.  
     
     
         3 . A composite material according to  claim 1  whereinthe bonded powder material reinforcement is zirconium tungstate.  
     
     
         4 . A composite material according to  claim 1  wherein the coefficient of thermal expansion of the composite material is between −1×10 −6 /° K and +1×10 −6 /° K over the temperature range of at least from about 0° C. to at least about 150° C.  
     
     
         5 . A composite material according to  claim 1  wherein the volume fraction of preformed bonded powder material reinforcement in the composite material is from about 40% to about 60%.  
     
     
         6 . A composite material according to  claim 1  wherein the volume fraction of preformed bonded powder material in the composite is substantially 50%, and the matrix material is aluminium or an aluminium alloy.