Microstructure and properties of graphene/TC11 composites fabricated by selective laser melting

Selective laser melting （SLM），as an additive manufacturing technology，can freely form high complexity metal parts. With different graphene nanoplatelets （GNPs） contents，GNPs/TC11 composites are prepared by SLM，and the effect of graphene content on the microstructure and physical properties of TC11 alloy formed by SLM is investigated. The microstructure indicates that graphene， as a carbon element， can dissolve into the TC11 matrix， resulting in a solution strengthening effect，and improve the heterogeneous nucleation rate of TC11 alloy that can promote phase α refinement. In addition，different degrees of element segregation are caused by graphene，triggering dislocation pinning effects and hindering deformation dislocation slip. The physical performance results show that the microhardness and strength of GNPs/TC11 composites are improved significantly，while the shape of TC11 wear marks transitions from U-shaped to W-shaped，and the size of wear marks and friction coefficient are reduced. When the load is 50 N，the surface roughness decreases by 43%，while when the load increases to 100 N，the surface roughness decreases by 14%. Additionally，its wear mechanism changes from adhesive wear to abrasive wear under 50 N load，during which the phenomenon of scale peeling is reduced. This indicates that adding GNPs to TC11 can improve its mechanical properties and wear resistance to a certain extent.