FATIGUE BEHAVIOUR OF COLD WORKED AI_2O_(3p)/AI6061 WITH DIFFERENT SURFACE TREATMENT

摘要

Low cycle fatigue (LCF) behaviour of cold worked Al_2O_(3p)/AA6061 paniculate reinforced metal matrix composites (PRMMCs) was investigated after various heat treatment and surface treatments. It was shown that the cold working degrades the LCF life and fatigue limit at 10~7 cycles somehow. Post heat treatment recovered almost tensile property and fatigue property. Shot-peening improved the fatigue resistance evidently, both for non-cold worked and cold worked materials. The microstructural damage by cold working is the main reason for the fatigue behaviour degradation. Shot-peening made the crack nucleation site move to deeper subsurface.