Unveiling the impact of heat treatment on powder-metallurgy α plus β titanium alloy for achieving a superior strength-ductility combination

The present study investigated the effects of heat treatment (solid solution and aging treatments) on the microstructure and mechanical properties of a hot-rolled alpha + beta Ti-3Al-5Mo-4.5V (TC16) produced through blended elemental powder metallurgy (BEPM) process using master alloy hydrogenation (MAH) approach. After solid solution treatment, metastable martensite alpha " phase and athermal omega phase were formed. Aging treatment facilitated decomposition of metastable phases and precipitation of alpha s particles. Dispersion strengthening, resulting from the formation of a significant amount of alpha/ beta interfaces between fine secondary alpha s particles and beta matrix, played a decisive role in enhancing the strength of the TC16 alloy. However, elevated aging temperatures promoted the coarsening of alpha s particles, leading to a reduction in the strengthening effect. A systematic investigation of the effects of the solid solution and aging treatments enabled the evolution of a bimodal microstructure with the precipitation of fine alpha s particles, contributing to an outstanding combination of strength and ductility. The ultimate tensile strength reached 1424.6 MPa with an elongation at break of 7.7%, while the hardness reached 380.2HV.