Correlation Between Heat-Treated Microstructure and Mechanical and Fretting Wear Behavior of Electron Beam Freeform-Fabricated Ti6Al4V Alloy

Heat treatments have been conducted on electron beam freeform-fabricated (EBF3-ed) Ti6Al4V alloy to obtain desired compressive and antifretting wear performance. The results suggested that the compression and fretting wear properties were significantly affected by the heat-treated microstructure. The subtransus heat treatment used in the present work created a homogeneous and coarser + lamellar structure with numerous fine secondary and nanoscale dispersoids inside. Such structural evolution accounts for the superior compressive property, high hardness, and fretting wear resistance. Additional findings revealed that the fine secondary and nanoscale dispersoids made a great contribution to the mechanical strengthening and especially passivation of crack propagation. This study shows that the as-received microstructure after EBF3 can be tailored by heat treatment to achieve favorable performance, which is significant for application of Ti6Al4V deposits.