Laser beam welding of NiTinol sheets in butt joint arrangement and optimization of the process using desirability function analysis and metaheuristic techniques

Abstract

Proper joining techniques of NiTinol, a widely used functional advanced material in many fields, would provide increased design flexibility among design engineers in terms of smart design for multifunctional systems. Laser welding is the widely utilized welding technique of NiTinol which can retain the superior characteristics of the material after welding. The effect of process parameters on the microstructure, mechanical properties, bead geometry, and new phase formation in butt welding configuration using fiber laser for a 2-mm thick NiTinol sheet was ascertained by this study. The scan speed, laser power, duty factor, frequency, and focal positions were used as input process variables, while microhardness and bead area were considered as output variables. Regression analysis was executed so as to create the input–output interactions. The optimization method was used with the goal of obtaining the smallest bead that met the condition of the bead having the least change in microhardness from the base material. The problem was devised as a constrained one and resolved using four metaheuristic techniques, such as Particle swarm optimization, Genetic algorithm, Jaya algorithm, and Bonobo Optimizer. The outcomes of these new procedures were also assessed using a traditional method called desirability function analysis. The results estimated utilizing all the different optimization techniques and the investigative data were established to be in excellent agreement.