Solid lubricating, hard and fracture resistant composites for surface engineering applications

Abstract

A method and composition for producing a monolithic hybrid composite consisting of a composite matrix, a reinforcement phase, and a solid/self-lubrication phase. The composition may comprise a graphite (“C”) phase and a titanium carbide (“TiC”) phase in a nickel (“Ni”) matrix. The process may include the step of blending pure Ni and pure titanium (“Ti”) powders with Ni-coated graphite powder using Laser Engineered Net Shaping (“LENS”). The novel composite, when achieved with an optimum chemical and structural phase ratio, exhibits a balance of high hardness, fracture toughness, and low friction/wear,

What is claimed: 
     
         1 . A monolithic hybrid composite comprising:
 a composite matrix;   a reinforcement phase;   and a solid/self-lubrication phase.   
     
     
         2 . The monolithic hybrid composite of  claim 1 , wherein the composite matrix is a nickel matrix. 
     
     
         3 . The monolithic hybrid composite of  claim 2 , wherein the nickel matrix is processed using pure nickel powder having a diameter of between about 40-150 μm. 
     
     
         4 . The monolithic hybrid composite of  claim 1 , wherein the solid/self-lubrication phase is graphitic carbon. 
     
     
         5 . The monolithic hybrid composite of  claim 4 , wherein the graphitic carbon is processed using nickel-coated graphite powder having a diameter of between about 40-150 μm. 
     
     
         6 . The monolithic hybrid composite of  claim 1 , wherein the reinforcement phase is titanium carbide. 
     
     
         7 . The monolithic hybrid composite of  claim 6 , wherein the titanium carbide is formed by reacting the pure titanium powder, having a diameter of between about 40-150 μm, with the graphitic carbon powder during the process. 
     
     
         8 . The monolithic hybrid composite of  claim 1 , wherein the ratio of the self-lubrication phase to the reinforcement phase, in atomic ratio, is about 7 to 4. 
     
     
         9 . A method of fabricating a monolithic hybrid composite, comprising the step of:
 blending elemental nickel powder and titanium powder together with nickel-coated graphite powder.   
     
     
         10 . The method of  claim 9 , wherein the atomic percent ratio of nickel:titanium:nickel-coated graphite powders are approximately 77:3:20, or Ni-3Ti-20C. 
     
     
         11 . The monolithic hybrid composite of  claim 10  exhibits optimum fracture toughness, hardness, and solid/self-lubricating properties.