Post weld heat treatment of friction stir welded AA2017

In this study a friction stir welded AA2017 is post weld heat treated at 500 °C for holding time of 20, 40 and 60min then quenched in water and naturally aged. The effect of post weld heat treatment on the microstructure and hardness is investigated across the transverse cross section of the weld. Experimental results showed that the PWHT causes abnormal grain growth of the grain structure mainly near to the advancing side of the weld. The grain size increases with the increase of the holding time however the region near to the retreating side of the weld retained its fine grain structure. EBSD has been used to examine the microstructure and texture before and after PWHT. EBSD investigation showed that the grain growth is texture dependant as grain growth occurs in some grains of (B+C) texture component while in the adjacent grains of texture components B-does not occur.