Abstract
In order to obtain aluminum alloy powder which composes of α-Al phase super-saturated with titanium and boron, the titanium and boron powders were mixed with various amounts of molar ratio Ti/B=1/2, to aluminum powder and then the mixture was mechanically alloyed for 108ks. The alloy powder was heat-treated for various times at 723-873K in argon atmosphere. It was observed that the structural change of the alloy powder with the heat-treatment by XRD, SEM and EPMA. When the Al-10-20mass%(TiB) powder heat-treated at 700-800K for treating time up to 3.6ks, Al3Ti, Al5Ti2 phases and diborid particles as TiB2 and AlB2 precipitate from the super-saturated α-Al phase, and these precipitates become to Al3Ti and TiB2 by the treating for long time. In the heat treatment at 873K for 3.6ks more than, Al3Ti phase ceased to exist, and only TiB2 existed in α-Al phase. The powder was consolidated at 873K for 5.4ks under various pressures. The Al-15-20mass%(Ti/B) alloys produced by the hot-pressing of about 300MPa become higher strength due to the precipitation-hardening and the dispersion of fine TiB2 particles.
