A Study on the Characterization of MASHS Processed Ti-Si-Al System

Many promising titanium aluminides and silicides could be synthesized in Ti-Si-Al system via mechanically activated self-propagating high-temperature synthesis (MASHS). The influence of mechanical activation and initial composition on phase formation, microstructure and synthesis behavior of mechanically activated Ti-rich mixtures in Ti-Si-Al system is investigated. Results indicate that Al can participate in the reaction and forms Ti3Al and TiAl3 phases beside Ti5Si3 phase by using mechanically activated reactants. Si and Al could be substituted each other in titanium aluminide and silicide to form solid solution of Ti3(Si,Al) and Ti5(Si,Al)3. In Ti-Si-Al system, combustion temperature is increased by increasing Si amount in the system while, ignition temperature is decreased profoundly from 1100 to 800 ∘C by applying mechanical activation prior to reaction and increasing Al in the system. In addition, Mechanical activation prior to synthesis gives rise to narrow grain size distribution and more uniform microstructure in comparison with SHS products.