Microstructure and high-temperature mechanical properties of near net shaped Ti-45Al-7Nb-0.3W alloy by hot isostatic pressing process

Near net shaped Ti-45Al-7Nb-0.3W alloy (at.%) parts were manufactured by hot isostatic pressing (HIP). The microstructure and high-temperature mechanical properties of the alloy were investigated by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that at a temperature of 700 degrees C, the peak yield stress (YS) and ultimate tensile stress (UTS) of alloy are 534 and 575 MPa, respectively, and the alloy shows satisfactory comprehensive mechanical properties at 850 degrees C. The alloy exhibits superplastic characteristics at 1000 degrees C with an initial strain rate of 5 x10(-5) s(-1). When the tensile temperature is below 750 degrees C, the deformation mechanisms are dislocation movements and mechanical twinning. Increasing the tensile temperature above 800 degrees C, grain boundary sliding and grain rotation occur more frequently due to the accumulation of dislocations at grain boundary.