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This research work analyses the thermal, metallurgical and physical stages of AISI 304 Stainless Steel-Copper dissimilar couple during laser welding in keyhole mode numerically and then validated experimentally. 10.6 μm wavelength CO2 laser welding machine is used for conducting this experimental analysis and the process is simulated by finite volume method. For making the dissimilar couple, a volumetric Gaussian heat source is applied symmetrically on the both metal domain and it is getting an asymmetric molten pool shape. It is observed that the computational model have good concurrence with the experimental results, after the calibration between simulation and experimental results for the same parameter set.

Continuous CO2 laser welding of an Fe-Cu dissimilar couple in a butt-weld geometry at different process conditions is studied. The process conditions are varied to identify and characterize the microstructural features that are independent of the welding mode. The study presents a characterization of the microstructure and mechanical properties of the welds. Detailed microstructural analysis of the weld/ base-metal interface shows features that are different on the two sides of the weld. The iron side can grow into the weld with a local change in length scale, whereas the interface on the copper side indicates a barrier to growth. The interface is jagged, and a banded microstructure consisting of iron-rich layers could be observed next to the weld/Cu interface. The observations suggest that solidification initiates inside the melt, where iron and copper are mixed due to convective flow. The transmission electron microscopy (TEM) of the weld region also indicates the occasional presence of droplets of iron and copper. The microstructural observations are rationalized using arguments drawn from a thermodynamic analysis of the Fe-Cu system.