Improved tensile properties of a novel near-α titanium alloy via tailoring microstructure by hot-rolling

Novel near-α titanium alloy sheets with improved tensile properties at room temperature and 650 °C were fabricated by hot-rolling. When rolled at 1000 °C, the sheet exhibits a duplex microstructure. When the rolling temperature is above 1025 °C, the basket-weave microstructure is obtained. Compared with the as-forged alloy, the intragranular microstructures of sheets are obviously refined. With increasing the rolling temperature, both volume fraction and mean size of silicieds decrease, and these silicides disappear completely when rolled at 1100 °C. The tensile strengths at both room temperature and 650 °C are significantly improved by hot-rolling. The UTS of all sheets at room temperature exceeds 1300 MPa. When rolled at 1100 °C, the UTS and elongation at 650 °C are 711 MPa and 24.4%, respectively. The strengthening mechanism at both room temperature and 650 °C is mainly attributable to the refined intragranular α platelets. In addition, the micro-voids are mainly induced by decohesion of the silicide/matrix interface at room temperature but by matrix damage at 650 °C.