Computational analysis of the intermetallic formation during the dissimilar metal aluminum-to-steel friction stir welding process:

The extent of inter-material mixing and the formation of intermetallic compounds play a critical role in the structural integrity and mechanical properties of the joints in the case of dissimilar metal friction stir welding. In general, there is a critical volume fraction of the intermetallic compounds in the mix zone of the friction stir welding-joint at which the mechanical properties of the joint are maximized. That is, insufficient inter-material mixing and the accompanying sub-critical volume fraction of the intermetallic compounds results in insufficient inter-material bonding and inferior joint strength. Conversely, super-critical volume fraction of the intermetallic compounds typically gives rise to the joint embrittlement. To address the problem of the effect of the friction stir welding process parameters on the extent of intermetallic compound formation, a multi-physics computational framework has been developed and applied to the case of dissimilar metal friction stir welding involving commerc...