Post weld heat treatment of continuous drive friction welded AA6061/SiC/graphite hybrid composites—an investigation

The continuous drive friction welding is a solid state, environment friendly welding method employed to join ferrous and non-ferrous materials. The paper aims at producing better quality joints using AA6061/SiC/graphite hybrid composite using continuous drive friction welding with post weld heat treatments. It investigates the effect of post weld heat treatments including solution treatment (ST) and solution treatment followed by ageing (STA) on mechanical and microstructural characteristics of continuous drive friction welded hybrid composite joints. The tensile properties were evaluated along with micro hardness and correlated with the microstructural characteristics with the primary focus on comparing the as-welded (AW) and post weld heat treated joints. The joint efficiency of STA joint is 73.82% and the ultimate tensile stress is 189 MPa. Final observations revealed that the grains appear relatively finer in the weld zone of the joint and increase in hardness after STA treatment. This may be the reasons for superior performance of STA joints and preferable microstructural characteristics compared to the ST and AW joints. (paper)