Effect of heat treatment on microstructure evolution of Ti-48Al alloy solidified under high pressure

High pressure solidification samples were prepared at 2 and 4 GPa on a HTDS-032F type cubic hydraulic pressure machine. Then, the samples were heat-treated at 1120℃ for 12 h. The effect of high pressure on the microstructure evolution of Ti-48Al alloy solidified under high pressure and heat treatment on the microstructure evolution of Ti-48Al alloy solidified under different pressures were investigated. The results indicate that, when solidified under high pressure, the γ-segregate phase decreases with increasing the pressure. When the pressure reaches 4 GPa, the volume fraction of lamellar structure is about 99.31%. After heat treatment, the microstructure solidified under normal pressure is not changed, but Widmanstä tten lamellar microstructure forms in high pressure solidified samples by NAKA mechanism, which is confirmed by heat treatment and EBSD analysis. ©, 2015, Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals. All right reserved.