Effect of process parameters on abnormal grain growth during friction stir processing of a cast Al alloy

The effects of process parameters and friction stir processing (FSP) run configurations on the stability of nugget microstructure at elevated temperatures were evaluated. Cast plates of an Al–7Si–0.6Mg alloy were friction stir processed using a combination of tool rotation rates and tool traverse speeds. All single pass runs showed some extent of abnormal grain growth (AGG), whereas multi-pass runs were more resistant to AGG. Additionally, higher tool rotation rate was found to be beneficial for controlling AGG. These effects were analyzed by comparing the result of this work with other published results and AGG models.