Influences of Nd additions on the microstructure and dry sliding wear behaviors of cast Al-Mg2Si in situ metal matrix composites were investigated. The results show that the addition of proper Nd addition has significant modification effect on both primary and eutectic Mg2Si in the Al-15 Mg2Si composites. The morphology of primary Mg2Si is changed from dendritic to polyhedral shape and the eutectic Mg2Si from flake-like to very short fibrous or dot-like

and their average particle sizes are significantly decreased also. The wear rates and friction coefficient of the composites with Nd are lower than those without Nd

and the addition of 0.5%Nd changes the wear mechanism of the composite from the combination mechanism of abrasive

adhesive and delamination wear without Nd into single mild abrasion wear.