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 α + β lamellar structure with numerous fine secondary α 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 α 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.