Effect of heating rate on porous TiAl-based intermetallics synthesized by thermal explosion

Abstract

ABSTRACTTiAl-based porous materials were synthesized by a novel process of thermal explosion (TE) reaction. The effects of heating rate on the expansion behavior of powder assemblies, phase compositions, and pore structures were investigated. Results showed that the actual temperature of specimen increased rapidly from 655 to 661°C (furnace temperature) to 1018–1136°C (combustion temperature) in a short time interval of 25–55 s, indicating that an obvious TE reaction occurred at different heating rates (1, 2, 5, and 10°C min−1). TE reaction in Ti/Al powder assemblies resulted in the formation of open-celled TiAl-based intermetallics. When the heating rate was set at 5°C min−1, the maximum open porosity of 59% was obtained in Ti-Al bodies, which experienced the highest combustion temperature (1136°C) and underwent maximum volume expansion (48%). The pore size distribution was uniform and pores were interconnected in TE products.