Microstructure and friction and wear behavior of fast solidified Mg-Si-RE (La, Ce) magnesium alloys

Abstract:

In this paper microstructure, friction and wear behavior under different loads of Mg-Si-RE magnesium alloys fabricated by rapid solidified process were studied. It was found that the microstructure of the fast-solidified state Mg-Si-RE alloy mainly consists of α-Mg matrix, eutectic Mg2Si phases and REMg2Si2 nano phases with 500-800 nm size. The relationship curve of friction coefficient and wear quantity with load of Mg-Si-RE alloy is determined. Results show that the friction and wear performance of Mg-Si-RE alloy is obviously better than that of Mg-1Si matrix alloy. The load of changed from slight wear to serious wear is lower than that of matrix alloy 20 N. And the wear amount is much smaller than that of matrix alloy at high load. The wear mechanism of Mg-Si-RE alloy includes oxidation wear, abrasive wear and delamination wear. The excellent friction and wear performance of RSP Mg-Si-RE alloy is mainly due to that the nano-scale rare earth phases were well dispersed along the grain boundary and within α-Mg matrix. Moreover, the Mg-Si-RE alloys exhibit different frictional wear behaviors after the addition of different types of rare earth elements.