3549 Effect of laser peening treatment on fatigue property in pre-cracked AC4CH

Abstract

To evaluate the effects of laser peening without coating on high cycle fatigue property, rotate-bending fatigue tests were conducted on pre-cracked AC4CH casting aluminum alloy. As the results, fatigue crack propagation was prevented by LP treatment. Apparent maximum stress intensity factor at surface on LP treatment specimen was nearly equivalent to about 4 times of threshold stress intensity factor of long fatigue crack at AC4CH when the surface crack began propagation. The cause of this threshold stress intensity factor increasing was effect of compressive residual stress by LP treatment.