Wear behaviour of Mg alloys and their composites - a review

Magnesium metal matrix composites (MMCs) have generated keen interest in recent times for potential usage in automotive and aerospace industries owing to their superior strength to weight ratio and high temperature resistance. With the concurrent attention to the requirements of high wear resistance and weight reduction, research into magnesium based MMCs has produced significant contributions in the automotive industry in the last few decades. Materials possessing high wear resistance under dry sliding conditions are associated with a stable tribo-layer on the worn surface and the formation of fine equiaxed wear debris. For abrasive wear, the influence of sliding speed, applied load, wearing surface hardness, reinforcement fracture toughness, percentages of reinforcement and morphology are critical parameters in relation to the wear regime encountered by the material. In this review, contemporary wear theories, issues associated with counter-face wear, and wear mechanisms are discussed in detail. Other areas of research relevant to abrasive wear of Al-based Mg alloys and Mg MMCs containing discontinuous reinforcement phases, such as the role of the reinforcement phase, are presented. Major effects such as interfacial transition, agglomerating phenomenon, formation, and distribution of in-situ Mg2Si, MgAl2O4, beta-Mg(17)Al(12)and MgO in the metallic matrix, filler-matrix bonding and phase transition are discussed in this article.