Superior strength-ductility balance in hot pressed swarf-Ti-6Al–4V alloy

Abstract

Ti–6Al–4V alloys were successfully fabricated by directly hot processing of the alloy swarf materials (having a size of 3 mm and 15 mm). The microstructure and mechanical properties of the hot-pressed swarf Ti-64 alloy and influence of starting swarf materials and heat treatment on the hot-pressed alloys were investigated. The hot-pressed swarf-Ti-64, made from 15 mm swarf that has a lamellar structure and 0.16% O, shows excellent strength-ductility balance, having a yield strength (YS) of 902 MPa, ultimate tensile strength (UTS) of 1016 MPa, and strain to fracture of 8.6%. After STA (solution treatment at 980 °C for 1 h, and then aging at 500 °C for 6 h), both alloy's strength and ductility were improved to a YS of 992 MPa, UTS of 1077 MPa, and strain to fracture of 17.3%. The strength-ductility combination of swarf-Ti-64 alloys is comparable or even better than the Ti–6Al–4V alloys manufactured by other approaches. It demonstrates that the hot processing is a promising process to produce high-quality Ti–6Al–4V alloy from the swarf materials.