Effect of Heat Treatment on the Microstructure and Mechanical Properties of Rotary Friction Welded Dissimilar IN718 to SS304L Alloys

The present study investigated the effect of heat treatment (pre- and post-weld) on microstructure mechanical properties an SS304L/IN718 dissimilar rotary friction welded alloy. Optical scanning electron micrographs joints in solution-treated (ST), aged (STA), post-weld (PWHT) conditions revealed defect-free welds. Furthermore, various zones were observed across weld region, namely fully deformed zone (FDZ), thermomechanical affected (TMAZ), (HAZ), base material (BM). Among welds with different (prior ST STA, PWHT), PWHTed exhibited excellent properties, which could be attributed to formation strengthening precipitates γ′ γ″ during double aging PWHT. In contrast, found poorest STA condition, possibly due dissolution welding. It was that failed HAZ SS304L side, away from interface, indicating region stronger than weakest metal (SS304L) joints.