Fabrication of thick intermetallic compound Al3Ti layer on metal substrateby combustion synthesis of ball-milled powder

A thick intermetallic compound Al3Ti layer was formed on a Cu or Ti substra te by a novel coating process, using combustion synthesis of a ball-milled Al-Ti powder mixture. The relation between the initial Ti particle sizes an d heat treatment conditions required to react with Al completely was estima ted by a spherical model incorporating diffusion kinetics to obtain homogen eous compound layer free from unreacted elements. Based on the calculated r elation, a homogeneous Al3Ti layer was formed by using finely ball-milled p owder particles with a microstructure such that Ti particles less than 1.0 mu m are dispersed in the Al matrix. This layer had almost the same wear pr operty and hardness as that of a cast Al3Ti.