Investigation of wear behaviour and microstructure of hot-pressed TiB2 particulate-reinforced magnesium matrix composites

Abstract

ABSTRACTIn this study, magnesium and magnesium metal matrix composites (Mg-MMCs) reinforced with 10, 20 and 30 weight (wt.)% TiB2 particulates were produced by powder metallurgy using the hot pressing technique. The hardness, density, wear behaviour and microstructure of samples were investigated. Uniform distributions of TiB2 particulates were observed except with some partial agglomeration for 30 wt-% TiB2. When compared to pure Mg, the hardness increment of Mg-MMCs reinforced with 10, 20 and 30 wt-%TiB2 particulates was 10.7, 31.9 and 65.3%, respectively. As compared to pure Mg, under load of 20 N, the decrease in wear rate in 10, 20 and 30 wt-% reinforcement was 28.71, 34.98 and 42.92%, respectively. It is believed that the reason of decrease in wear rate was the presence of harder TiB2 particulates, which resisted to wear and plastic deformation. For pure Mg, oxidative wear changed to oxidative and mild abrasive wear transition from 10 to 20 N. Mg/TiB2 composites exhibited abrasive wear mechanism under load of 10 and 20 N except 30 wt-% TiB2 composite indicated oxidative and adhesive wear. However, a transition from mild abrasive wear to severe abrasive wear was observed with increasing load in composites.