A Review on Pre/Post Treatments Used in Friction Stir Welding

The detail review is focused in this paper corresponding to various pre/post treatments used in friction stir welding (FSW). These are, isothermal ageing, solution heat treatment, natural ageing, post weld aging, ARB (Accumulative Roll-Bonding), immediately pouring of water and mechanical powder mixing. Introducing the shielding gas around the tool, ultrasonic assisted aging is also discussed. The change in microstructural and mechanical properties, distributions of the microstructures and hardness is reviewed. The effect of the FSW process on matrix grain size and reinforcement particles is evaluated. Formation of intermetallic phases under the influence of power ultrasonic process is studied. The flow patterns are analyzed. The influence of single and multi-pass friction stir processing on the structure and mechanical properties is also discussed. The upcoming research is going in the field of microstructural and mechanical properties stabilization in a single process of FSW. A systematic literature review based on the different pre/post FSW treatments and their effects on microstructural and mechanical properties is highlighted in this paper.