Thermo-mechanical analysis in pulsed laser cladding of WC powder on Inconel 718

Abstract

An uncoupled thermo-mechanical finite element model is developed to simulate the laser-cladding process of tungsten carbide (WC) on Inconel 718. First, a non-linear three-dimensional transient thermal model is developed, which calculates transient temperature distribution in the local clad area. Thermal load attributed to laser beam is implemented to the workpiece by using a developed subroutine. Thermal and mechanical material properties are introduced temperature dependent. All the major physical phenomena associated to the laser-cladding process, such as heat radiation, thermal conduction, and convection heat losses, are taken into account in the developed model. Subsequently, using the thermal history of the thermal analysis, a mechanical analysis is performed, from which the residual stresses are calculated. Both thermal and mechanical analysis results are verified through experimental works. Results show that the temperature profile and clad dimensions are strong function of the heat source and conductivity of material. It is concluded that the laser power and cladding velocity have significant effect on residual stresses. Also, it is found that the longitudinal stresses are approximately three times the transverse ones. Results of mechanical analysis reveal that by increasing input energy, residual stresses increase and number of cracks decreases in the cladded layer.