Hybrid Friction Stir Welding of Similar and Dissimilar Materials

Abstract

Hybrid friction stir welding is an innovative solid-state joining technology which has great potential to produce effective and defect-free joint for similar materials and dissimilar materials irrespective of high chemical affinity and completely different physical and mechanical properties like aluminium and copper. Among the possible preheating source, plasma arc provides unique combination of high arc stability, concentrated energy density and low equipment cost. Plasma arc usually coupled with various manufacturing system in order to enhance the performance of conventional machining and bonding processes. Hence, plasma-assisted friction stir welding (P-FSW), as a hybrid system, is investigated in order to improve the weld joint quality and joint efficiency. Preheating effect using plasma arc, the P-FSW of aluminium alloy and other high-strength alloys enables to decrease the plunging force and enhance mechanical properties of welded joint. The integration of plasma arc on FSW tool also aids to decrease the probability of formation of welding defects. In present work, an overview of plasma-assisted friction stir welding (P-FSW) is presented by means of experimental investigation and prediction of it through numerical modelling. Finite element-based simulation using ABAQUS is carried out to evaluate the temperature profiles. A comparative study of mechanical and macro-microstructural characterizations of weld joint by conventional FSW and P-FSW processes has been conducted on similar (AA1030) and dissimilar (AA1100-pure copper) materials joining. Overall, the influence of preheating acts quite homogeneously throughout the structure as compared to conventional FSW. However, the results reveal that the development of P-FSW is still in initial stage and needs to improve in various aspects. Although P-FSW process is quite effective to improve mechanical properties and reduction of plunging forces, it needs to investigate the potentiality for relatively harder materials and dissimilar materials joining.