Dry wear behavior of rheo-casting Al-16Si-4Cu-0.5Mg alloy

Dry wear behavior of the rheo-casting Al-16Si-4Cu-0.5Mg alloy was investigated by micro-scratch and dry sliding wear tests. Analyses of the microstructure, scratch grooves, wear tracks, worn surfaces and wear debris of the alloy were carried out by optical microscope and scanning electron microscope. The microstructural analysis showed that via rheo-processing, the primary Si was refined and rounded, eutectics dispersed more homogenously, and even the skeleton AlFeMnSi phase was fragmented into facet shape. Micro-scratch test showed that the microstructural refinement resulted in better wear resistance. Dry sliding wear test revealed that the rheo-processed sample exhibit obviously superior wear resistance because of the microstructure improvement. The dominant mechanism in mild wear condition is abrasion, but it turned to adhesion and oxidation in high applied load and fast sliding velocity conditions.