Microstructure and mechanical properties of Ti6Al4V alloys fabricated by additive friction stir deposition

The additive friction stir deposition (AFSD) of Ti6Al4V alloy was successfully performed over a wide processing window. The microstructures were examined based on the high atemperature β grain size, grain boundary α formation and the propensity of variant selection as a function of process parameters. The analysis revealed that a reduction in deposition temperature could be achieved by the change in AFSD parameters, resulting in major reduction of prior β grain size and refinement of as-deposited α phase structure. This resulted in significant improvements of ductility and strength in the as-deposited state with ductility values up to ∼20% and maximum yield and ultimate tensile strengths values of 1010 MPa and 1233 MPa, respectively.