Solidification of quaternary X5CrNi18-10 alloy after laser beam welding: A phase-field approach

The austenitic stainless steel (X5CrNi18-10) is the most commonly used chrome-nickel steel, due to its high corrosion resistance. However, it faces the challenge of cracking events during post-laser-beam-welding dendritic solidification. These microstructural changes significantly impact the final mechanical properties. To contribute to a more precise understanding of the physical mechanisms of the appearance of cracking, the goal of this research is to investigate various aspects at the microscale influenced by process-specific extreme thermal conditions. A thermodynamic model of quaternary alloy configuration is used to study the micro-segregation behavior of alloying elements and resulting morphology based on the local thermal conditions. For this purpose, a multi-component and multiphase-field-based grand chemical potential model is used. It is observed that in addition to global processing conditions, local conditions are also important to consider and classify the morphology changes from columnar-dendritic to cellular along the liquidus isotherm of the weld pool.