Microstructure-property evolution of mechanically alloyed Al-20 wt% Si matrix powders and sintered composites reinforced withTiB₂particulates

Microstructural, physical and mechanical properties of Al-20 wt% Si matrix alloy powders and those rein-forced with TiB2 and their sintered composites were investigated in relation to TiB2 content and mechan-ical alloying (MA) durations. Al-20 wt% Si matrix alloy powders and those containing 5 and 10 wt% TiB2 reinforcing particles were MA'd for 1, 2, 4, and 8 h followed by consolidation and sintering at 843 K. Si solubility in a-Al matrix increased with increasing MA duration. Increasing the TiB2 content, on the other hand, resulted in a systematic drop in Si solubility over the same MA period. Scanning electron micro-graphs of the sintered samples revealed sub-micron-sized, rod-shaped Si and spherical Al9Si phase par-ticles. With increasing TiB2 content and MA durations, the microhardness of the Al20Si/TiB2 composites improved. The wear resistances of TiB2 reinforced composites better by 5 to 8 times than that of the as -blended and 1 h MA'd AlSi matrix alloy. Due to the presence of the Al3Ti intermetallic phase, sintered composite samples containing 10 wt% TiB2 particles MA'd for 8 h had the maximum hardness value and lower wear resistance values than those of the Al-20 wt% Si/5 wt% TiB2 composites.(c) 2023 Karabuk University. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).