Effects of heat treatment on TiH_2decomposition behavior and microstructure

Based on the two-step foaming process of melt route precursor for fabricating net-shape products of foamed aluminum, the oxidation process of TiH2, the continuous decomposition characteristics, the isothermal decomposition behavior, and the microstructure of oxidized TiH2 were studied. The results show that the starting decomposition temperature of TiH2 can be elevated by the oxidation, and increases with the increasing of heat-treated temperature.The isothermal decomposition curve of oxidized TiH2 consists of three parts: a low-level decomposition platform, a rapid decomposition phase, and an even decomposition phase. The duration of the low-level decomposition platform is increased with the increasing of oxidation temperature. The decomposition volume of TiH2 treated by 400 ℃/6 h+500 ℃/1 h+620 ℃/30 s is larger than that of TiH2 treated by 400 ℃/6 h+500 ℃/1 h.The dense oxidation layer of TixOy with 1.1～1.5 μm TixOy on the surface of TiH2 produced by heat treatment at 300～550 ℃ consists of TiH1.97—TiH1.97+TiO2—TiH1.97+TiO2+T2O—TiH1.97+TiO2+T2O+TiH sequentially.