Effect of TiH2 on the Microstructures and Refining Performance of Al-Ti-C Master Alloy

Al-Ti-C master alloy with or without the TiH2 was prepared by Self-propagating High-temperature Synthesis (SHS) induced by laser. The phases, composition, microstructure morphologies of master alloy and its thermal reaction process were investigated by XRD, EPMA, DTA and SEM. The results show that adding TiH2 has obvious effect in promoting the synthesizing reaction of Al-Ti-C master alloys. Active Ti atoms and catalyzing H atoms released by TiH2 thermal decomposition cause critical reacting temperature of the SHS decreasing. The addition of TiH2 affects the morphologies and distribution of TiAl3 and TiC particles (size of TiC was smaller than 1μm in diameter), and restrains the congregating tendency of TiC particles. The refining test on aluminum indicates that master alloys with TiH2 possesses more excellent grain refining perfprmance than without, because of the composition and morphology of the master alloy is cut out for refining processing.