Dry sliding wear behaviour of Mg–Si alloys

This study aims to investigate the dry sliding wear behaviour of pure Mg, different hypo (Mg–0.5, 0.7, 1.15wt% Si) and hyper (Mg–2, 4, 6, 8 and 10wt% Si) eutectic Mg–Si alloys prepared using the gravity casting method. Various parameters such as alloy composition, normal loads with constant sliding speed and sliding distance have been used to study the wear behaviour of these alloys using pin on disc configuration against a hardened chromium steel counter face. Detailed microstructural morphology studied for the pure Mg and the Mg–Si alloys are correlated with the wear properties obtained. The hypereutectic alloys yield better wear resistance as compared to the hypoeutectic Mg–Si alloys because of the presence of coarse and hard primary Mg2Si particles. The SEM analysis carried out on the worn surfaces and wear debris to understand the wear mechanisms. The size and volume of Mg2Si phase play an important role in deciding the wear behaviour of the Mg–Si alloys. ► Wear rate of Mg–Si alloys reduced with increase in Si content. ► Wear resistance decreases with increase in load. ► Hypoeutectic Mg–Si alloys adhesive wear followed by oxidation play a major role. ► Hypereutectic Mg–Si alloys up to about 6wt% Si delamination wear dominate. ► Above 6wt% Si abrasion wear is the main mechanism.