Tribological effects of carbon nanotubes on magnesium alloy AZ31 and analyzing aging effects on CNTs/AZ31 composites fabricated by stir casting process

The tribological behavior of AZ31 Mg alloy reinforced with multiwall carbon nanotubes (MWCNTs) was studied through experiments on a ring-on-block wear testing apparatus against 45C steel. The composites were successfully fabricated using stir-casting processing with different percentages of MWCNTs and then age hardened for 10 h. The effect of the various concentrations of MWCNTs on the microstructures, tribological properties, and wear mechanisms of the composites were systematically examined by scanning electron microscopy (SEM). With increasing percentage content of MWCNTs, the wear rate and the coefficient of friction decreased, which is attributed to the microhardness and self-lubricating properties of the MWCNTs. The microstructure characterization results established different mechanisms-specifically, abrasion, oxidation, and delamination-and very small plastic deformation.