Analysis of heat generation during friction stir welding of aluminum alloy 2024-T4 and its impact on joint characteristics

Friction stir welding (FSW) is a successful welding technique for joining of aluminium and many other materials with the required joint configurations. During this welding process, large amount of heat is generated, which influences the integrity, performance, and microstructure of the weld joints. In this study, both experimental and numerical approaches are adopted to analyse the influence of heat generation on the metallurgical and mechanical properties of friction stir-welded joints of AA2024-T4. A computational fluid dynamics (CFD) model is constructed for quantitative analysis of heat flux, heat generation, temperature distribution, strain rate and viscosity. The model is validated by experimentally measured temperature data, and both agree well. The results showed that both heat flux and strain rate are more or less symmetric about the tool axis whereas plastic material flow is asymmetric. Heat flux affects the grain size and mechanical properties of the joint.