Abstract:A series of Al−Ti−B master alloys were prepared by different preparation routes, and the TiB₂ particles in the master alloys were extracted and analyzed. It is found that the forming process has significant influence on the three-dimensional morphology of TiB₂ particles. Different preparation routes result in different reaction forms, which accounts for the morphology variation of TiB₂ particles. When the Al−Ti−B master alloy is prepared using “halide salt” route, TiB₂ particles exhibit hexagonal platelet morphology and are independent with each other. In addition, the reaction temperature almost does not have influence on the morphology of TiB₂ particles. However, TiB₂ particles exhibit different morphologies at different reaction temperatures when the master alloys are prepared with Al−3B and Ti sponge. When the master alloy is prepared at 850 °C, a kind of TiB₂ particle agglomeration forms with a size larger than 5 μm. The TiB₂ particles change to layered stacking morphology even dendritic morphology with the reaction temperature reaching up to 1200 °C.

Key words: Al−Ti−B alloy; TiB₂; forming process; three-dimensional morphology