Effect of friction stir processing conditions on fatigue behavior and texture development in A356-T6 cast aluminum alloy

Friction stir processing (FSP) was applied to A356-T6 cast aluminum alloy to modify the microstructure and to eliminate casting defects under two different tool rotational speeds. Plane bending fatigue tests had been conducted, revealing that FSP could enhance the fatigue strength where the lower rotational speed condition gave better results. The enhancement of fatigue strength was attributed to the elimination of casting defects. Crystallographic analysis by EBSD revealed that the texture induced by FSP had detrimental effect on growth resistance. The lower rotational speed condition resulted in the weaker texture, and consequently, further increase of fatigue strength was achieved compared with the higher rotational speed condition. (C) 2015 Elsevier Ltd. All rights reserved.