Anisotropy in Nanoscale Friction and Wear of Precipitate Containing AZ91 Magnesium Alloy

In the present study, nanoscale friction and wear behavior of microstructure containing continuous precipitates (CPs) and discontinuous precipitates (DPs) in an aged AZ91 magnesium alloy has been evaluated using atomic force microscopy (AFM). The influence of sliding direction with respect to precipitate alignment on friction and wear response has been examined and is compared with pure magnesium. DP regions showed lowest values of friction and wear, followed by CP regions and pure Mg. In addition, for DP regions, a strong dependence of frictional force and wear on precipitate alignment with respect to the sliding direction was observed. The quantitative difference in measured friction and wear due to direction dependence can be understood with model proposed by Yu et al. and taking into account the effective contact area between the precipitate regions and the AFM probe.