Effect of reinforcement type on microstructural evolution and wear performance of copper matrix composites via powder metallurgy

Powder metallurgy (PM) route was used to prepare copper matrix composites (CMCs). The reinforcement (B₄C, fly ash, and W) and the copper particles were blended, compacted, and sintered. The microstructures revealed that each reinforcement particle was homogeneously dispersed in the respective composites. A proper interfacial bonding was obtained without pores or interfacial reactions. XRD patterns did not reveal any foreign compounds or oxides. All kinds of reinforcement particles caused grain refinement of the copper matrix and reduced the wear rate and the COF. Cu/B₄C CMC showed higher wear resistance than Cu/fly ash and Cu/W CMCs. The worn surface was analyzed using SEM and a 3D profilometer. Reinforcement particles arrested the subsurface damage causing a change in wear mode. The composites produced smaller debris during sliding wear in contrast to large chunks produced by the copper matrix. All kinds of reinforcement particles reduced the electrical conductivity of the copper matrix. The criteria for choosing a particular reinforcement for CMCs are critically discussed.