Numerical and experimental analysis of molten pool dimensions and residual stresses of NiCrBSi coating treated by laser post-remelting

Three-dimensional simulation model was developed to simulate the thermal and mechanical behaviors of NiCrBSi coatings during laser post-remelting. The post-remelting process of plasma sprayed coatings was performed by a pulsed laser with Gaussian distribution. A numerical model allowing predicting single-pass laser remelting of a thick coating was implemented to investigate the dimensions of the molten pool as a function of processing parameters. The computed results were then validated by the comparison with the corresponding experimental ones. In addition, the thermomechanical model consisting of a beam sample with a length of 80 mm was implemented to evaluate the evolution of the specimen deformation, and residual stress distribution during laser post-remelting. In the case of a NiCrBSi coating elaborated on a stainless steel substrate (316 L), the results indicate that residual stresses within the remelted coating are tensile, while that within the unremelted region of the coating alongside the remelted track are compressive. Finally, the effects of the efficiency of the cooling device on the residual stress distribution were investigated.