Processing-structure-property correlation in additive friction stir deposited Ti-6Al-4V alloy from recycled metal chips

Abstract Additive friction stir deposition (AFSD) is a novel thermo-mechanical solid state additive manufacturing process. AFSD enables manufacturing of near net shape, fully dense builds with refined equiaxed grain structure resulting in excellent mechanical properties. AFSD has the potential to produce ingots and components/builds from recycled metals (chips/scraps/wastes from industrial machining processes or municipal recycling centers). In the present study, recycled Ti-6Al-4V alloy chips were deposited using additive friction stir deposition. Detailed microstructural and mechanical property investigation of the deposited material fosters understanding of the effect of deposition variables on the microstructure as well as mechanical properties. The as-deposited microstructure was characterized by lamellar α/β colonies inside fine equiaxed prior β grains containing α phase at the grain boundary. Additive friction stir deposited Ti-6Al-4V alloy using consolidated recycled metal chips as raw material exhibited tensile properties better than other additive processes; thus, AFSD of recycled metal provides opportunities to produce structurally sound components with reduced energy consumption as well as reducing environmental waste.