1997 Volume 44 Issue 12 Pages 1100-1106
Infiltration-combustion reaction between Ti green compact and molten Al was studied. The infiltration height change obtained by in-situ measurement, showed a linear proportion to the root of immersing time, but an incubation period was observed in the initial stage of the immersion. Using thermocouple embedded in the Ti green compacts, the combustion temperature of Ti powder and molten Al was determined to be about 1360K, which is lower than the calculated adiabatic temperature, 1580K, of the combustion synthesis of TiAl3. In the preform immersed into molten Al for 30s, granular products were observed at the surfaces of Ti particles. By the observation on the helium-gas-quenched sample, it was confirmed that disintegrated Ti particles and spherical particles of TiAl3 were formed. The crevice between the as-reacted TiAl3 particles was found to be filled with molten Al by the further infiltration to form Al/TiAl3 composite. The final microstructure of this reaction is a cermet type one with about 74 vol% of TiAl3 and the average particle size is about 12μm.
