Welding of dissimilar material of Fe and Al with modeling of intermetallics

The strength of aluminum to steel dissimilar alloy joints is determined by the magnitude of brittle intermetallic compound layer formed at the interface. The growth of the intermetallic compounds such as FeAl, FeAl₂, and Fe₂Al₅ is controlled by the thermal history during the joining process. A multi-physics multi-phase field model has been developed to predict the intermetallic compound layer formed during joining reactions between iron (Fe) and aluminum (Al). The multi-physics laser welding model is applied to simulate the laser keyhole welding process with varying laser power and welding speed. The thermal history at the joint interface is incorporated into the phase field model to simulate the microstructural evolution of the intermetallic compound layer. Simulation results were then analyzed and validated with the experimental results in terms of morphology of intermetallic compound grains and evolution of different phases. The multi-physics multi-phase model is used to optimize the laser welding parameters to minimize the thickness of the intermetallic compound layer and thus retain the mechanical properties of base materials.