Microstructure and Mechanical Properties of Friction Stir Processed A356 Cast Al under Air Cooling and Water Cooling

Abstract

AbstractIn this work, friction stir processing (FSP) was used to modify the microstructure of A356 cast aluminum alloy under air cooling and water cooling conditions. The microstructure and mechanical properties of air cooling and water cooling FSP specimens and their differences were mainly discussed. Results show that the grains can be significantly refined after FSP under both air cooling and water cooling conditions. The water cooling FSP specimen shows much smaller grains than the air cooling FSP specimen due to lower temperature. Similarly, the Si particles of water cooling FSP specimen show much smaller sizes and better distribution. Both the air cooling FSP specimen and water cooling FSP specimen own much higher tensile strength and elongation than A356 base material (BM). In particular, the tensile strength and elongation of water cooling specimen are respectively 231 Mpa and 14.15%, which are equal to 186.3% and 1088.5% of the BM. Furthermore, the microhardness of water cooling FSP specimen is lower than that of the air cooling FSP specimen.