Materials Science Forum, Vol.449-4, 201-204, 2004
Combustion synthesis process of Ag added Al3Ti intermetallic compound
The effect of Ag addition to the mixture of Al and Ti on the densification of synthesized Al-Ti intermetallic compounds was examined. By the Ag addition, ignition temperature to form Al3Ti was lowered to the eutectic temperature of the Al-Ag alloy. When elemental powder mixture with 2% Ag was continuously heated to 973K under the uniaxial pressure of 1.0MPa, void ratio of sintered compact was reduced to 0.1% and the densification was enhanced by increasing the composition of Ag. Al3Ti and Ag2Al were formed in the as sintered compact and Ag2Al decomposed to solve Ag into Ll(2)-Al3Ti by further heating at 1073K for 14.4ks. Although Ag addition decreased the hardness of sintered compact lower than that of Al3Ti, it still retained the hardness of about 40OHv for 12% Ag added specimen. The sintered compact was hardly damaged after oxidizing at 1273K for 230.4ks due to the formation of protective Al2O3 surface scale.
Keywords:titanium aluminide(Al3Ti);intermetallic compound;powder metallurgy;combustion synthesis;hot press