Effect of β forging and heat treatment on the microstructure and mechanical properties of powder TC4 titanium alloy

Mechanical properties, especially fatigue properties, of low-cost powder pressureless sintered titanium alloy components are generally inferior to those of forged titanium alloys, while their mechanical properties can be effectively enhanced by subsequent hot working. In this paper, the effects of β forging and solution and aging heat treatment on the microstructure and mechanical properties of TC4 (Ti-6Al-4V) titanium alloy billets prepared by pressureless sintering were studied. It is indicated that β forging significantly reduces the pore size of the as-sintered billet and greatly improves the relative density. The as-forged alloy exhibited excellent room-temperature tensile properties, with tensile strength of 972 MPa and elongation after fracture of 16%. In addition, smaller size of residual pore in the powder TC4 titanium alloy billet after β forging significantly improved the fatigue performance compared to the sintered alloy. After solution and aging heat treatment, the powder alloy achieved more than 10? cycles under the conditions of a maximum stress of 480 MPa and a stress ratio of 0.1.