The high-temperature deformation behavior of a novel near-alpha titanium alloy and hot-forging based on the processing map

摘要

Limited by the composition, the service temperature of high-temperature titanium alloys have been restricted to 600 degrees C for many years. In this study, a self-designed Ti-6Al-3Sn-10Zr-(Mo, Nb, W, Si) near-alpha titanium alloy that can be used at 650-700 degrees C was fabricated by vacuum arc remelting (name as DsTi700). Isothermal compression tests were performed at 975-1100 degrees C and in the strain rate range of 0.01-1 s(-1). The results indicate that the flow behaviors of DsTi700 alloy under high strain rate are different from that of some traditional near-alpha titanium alloys and the peak stress values are generally higher than those of some common near-alpha titanium alloys at the same/similar deformation conditions. The deformation activation energy Q in beta phase field is 240.2 kJ/mol. Moreover, the processing map were developed to determine the optimal processing window. Finally, DsTi700 alloy pancake with basket-weave microstructure was successfully prepared by multi-pass hot-forging. Tensile tests exhibit that the elongation of DsTi700 alloy at room temperature is nearly 13%, the UTS exceeds 600 MPa at 650 degrees C, which is almost equal to the UTS of some traditional near-alpha titanium alloys at 600 degrees C. Moreover, the UTS and elongation of DsTi700 pancake are 511 MPa and 24.1% at 700 degrees C.