Effects of Hot Isostatic Pressing and Heat Treatment on the Microstructure and Mechanical Properties of Cast TiAl Alloy

Hot isostatic pressing (HIP) and subsequent heat-treatments (HT) are necessary for titanium aluminide (TiAl) casting components. But there few studies carefully comparing the microstructure changes from initial as-cast condition to final heat-treated condition. In this study, microstructures of Ti-47Al-2Cr-2Nb (at%) alloy in as-cast, as-HIPed as-heat-treated conditions were characterized by optical microscopy scanning electron microscopy. The mechanical properties after HTs determined tensile tests at 700 °C. results show that HIP HTs, all exhibit a nearly lamellar (NL) structure can be divided into an edge region central area. is normal, while distorted lamellae many fine recrystallized grains exist yield strengths three same, but elongation HT 1310 °C much more than 1185 1280 A refinement colony size induced considered responsible great improvement elongation.