Effect of friction stir processing on plain fatigue and fretting fatigue behaviour of the AA6063 alloys

The present work investigated the effect of friction stir processing (FSP) on the plain fatigue and fretting fatigue of the AA6063 alloys. The FSP had noticeably smaller grains than the base material. The ultimate tensile strength of the FSP increased by 31.6 %. The fatigue life of the FSP specimen was improved by approximately 10 % in plain fatigue and 28.3 % in fretting fatigue. Increment in life is caused by grain refinement and increased compressive stress. The fretting wear damage and value of the coefficient of friction were observed to be more significant in the case of base material instead of FSP. For base and FSP materials, the life was reduced by 1.6 and 1.18 times, respectively, due to fretting fatigue over plain fatigue.