Compliant Layer for Matched Tool Molding of Uneven Composite Preforms

Abstract

A method for consolidating a preform made of composite material. The preform and a compliant metal alloy sheet are placed between less compliant matched confronting forming/molding surfaces with the preform being sandwiched between the metal alloy sheet and a matched confronting surface. The matched confronting surfaces and compliant metal alloy sheet are heated until the preform reaches at least its consolidation temperature. During heating, force is applied so that the matched confronting surfaces exert sufficient compressive force on the preform and metal alloy sheet to cause the composite material to consolidate at the consolidation temperature. The metal alloy sheet has a tensile yield point in a range of 25-300 psi at the consolidation temperature at a strain rate of about 1% to 10% strain per minute.

1 . A method for consolidating a preform made of composite material, comprising:
 placing the preform and a metal alloy sheet between first and second tool assemblies having matched confronting surfaces which are less compliant than the metal alloy sheet, with the preform being sandwiched between the metal alloy sheet and one of the matched confronting surfaces;   heating the matched confronting surfaces of the first and second tool assemblies and the metal alloy sheet until the preform reaches at least a consolidation temperature of the composite material; and   applying force to one or both of the first and second tool assemblies so that the matched confronting surfaces exert sufficient compressive force on the preform and metal alloy sheet to cause the composite material to consolidate at the consolidation temperature,   wherein the metal alloy sheet has a tensile yield point in a range of 25-300 psi at the consolidation temperature at a strain rate of about 1% to 10% strain per minute.   
     
     
         2 . The method as recited in  claim 1 , wherein the metal alloy sheet is made of magnesium base alloy. 
     
     
         3 . The method as recited in  claim 2 , wherein a chemical composition of the magnesium base alloy includes magnesium, aluminum, zinc and manganese. 
     
     
         4 . The method as recited in  claim 1 , wherein the metal alloy sheet is made of aluminum base alloy. 
     
     
         5 . The method as recited in  claim 1 , wherein the metal alloy sheet is very soft at the consolidation temperature. 
     
     
         6 . The method as recited in  claim 1 , wherein the composite material comprises a matte product. 
     
     
         7 . The method as recited in  claim 6 , wherein the matte product comprises recycled graphite fibers. 
     
     
         8 . The method as recited in  claim 7 , wherein the matte product further comprises thermoplastic fibers. 
     
     
         9 . The method as recited in  claim 6 , wherein the composite material comprises graphite fibers and plastic material. 
     
     
         10 . An apparatus for consolidating a preform made of composite material at a consolidation temperature, comprising:
 first and second tool assemblies having matched confronting surfaces;   a metal alloy sheet disposed between said matched confronting surfaces, wherein said metal alloy sheet has a tensile yield point in a range of 25-300 psi at the consolidation temperature at a strain rate of about 1% to 10% strain per minute;   means for heating at least said matched confronting surfaces of the first and second tool assemblies; and   means for applying force to one or both of the first and second tool assemblies so that said matched confronting surfaces are capable of exerting compressive force on the preform and metal alloy sheet.   
     
     
         11 . The apparatus as recited in  claim 10 , wherein said metal alloy sheet is made of magnesium base alloy. 
     
     
         12 . The apparatus as recited in  claim 11 , wherein a chemical composition of the magnesium base alloy includes magnesium, aluminum, zinc and manganese. 
     
     
         13 . The apparatus as recited in  claim 10 , wherein said metal alloy sheet is made of aluminum base alloy. 
     
     
         14 . The apparatus as recited in  claim 10 , wherein the metal alloy sheet is very soft at the consolidation temperature. 
     
     
         15 . The apparatus as recited in  claim 10 , wherein each of said first and second tool assemblies comprises a respective susceptor, said susceptors forming said matched confronting surfaces. 
     
     
         16 . A method for consolidating a composite preform made of recycled graphite fibers and organic resin fibers, comprising:
 placing the composite preform and a metal alloy sheet between matched confronting surfaces of first and second tool assemblies, the matched confronting surfaces being less compliant than the metal alloy sheet;   heating the matched confronting surfaces of the first and second tool assemblies and the metal alloy sheet during a heating cycle; and   applying force to one or both of the first and second tool assemblies so that the matched confronting surfaces exert sufficient compressive force on the composite preform and metal alloy sheet to cause one side of the composite preform to be thermally coupled to one side of the metal alloy sheet, the other side of the composite preform to be thermally coupled to one of the matched confronting surfaces, and the other matched confronting surface to be thermally coupled to the other side of the metal alloy sheet, said force being applied during at least a portion of the heating cycle,   wherein the metal alloy sheet has a tensile yield point in a range of 25-300 psi at a consolidation temperature at a strain rate of about 1% to 10% strain per minute.   
     
     
         17 . The method as recited in  claim 16 , wherein the metal alloy sheet is made of magnesium base alloy. 
     
     
         18 . The method as recited in  claim 17 , wherein a chemical composition of the magnesium base alloy includes magnesium, aluminum, zinc and manganese. 
     
     
         19 . The method as recited in  claim 16 , wherein the metal alloy sheet is made of aluminum base alloy. 
     
     
         20 . The method as recited in  claim 16 , wherein the metal alloy sheet is very soft at the consolidation temperature.