Friction welding of selective laser melted Ti6Al4V parts

Ti6Al4V alloy samples fabricated by selective laser melting (SLM) were subjected to solid-state welding friction welding (FW). The welded alloy exhibits a alpha'-martensitic microstructure in the form of platelets with dimensions in the submicron regime. The base alloy has a relatively coarser microstructure consisting of both alpha' and beta phases, as compared to the as-prepared SLM microstructure (single-phase cemartensite). Hardness measurements revealed an increase of hardness in the weld zone due to the refined alpha'platelets. A marginal drop in hardness along the base alloy is observed that may be attributed to the imposed thermal cycle during the FW process. Tensile tests reveal an improved ductility for the FW samples at the expense of a marginal drop in strength, compared to the as-prepared SLM samples. The present work illustrates the ability of solid-state welding processes for successfully joining SLM parts and in improving, the ductility of the SLM parts and offers the opportunity to work with the additive manufacturing processes without size limits.