Effect of Tool Rotation Speed on the Microstructure and Mechanical Properties of Al-12.7 % Si Alloy by Friction Stir Processing

Abstract

FSP was applied to the as-cast Al-12.7Si alloy at a traverse speed of 150mm/min and different rotation speeds (700rpm to 1000rpm). The coarse α-Al dendrites and eutectic Si phase can be refined by friction stir process. After FSP, Si particles are homogeneously distributed in the Al matrix with equaixed grains. Tool rotation speed has an effect on the microstructure and mechanical properties of the Al-12.7Si alloy. The size of Si particles decreases and that of the Al matrix grains increases with increase of the rotation speed. The microhardness values of the stir zone increase with increase of rotation speed. With rotation speed increases, the ultimate tensile strength is slightly increased and the elongation is greatly improved.