Influence of heat source model on the behavior of laser cladding pool

Abstract

The reflection of the laser energy by the powder makes the laser energy no longer exhibit a Gaussian distribution. The purpose of this paper is to investigate the effect of the heat source model on the behavior of the molten pool in laser cladding. First, the Gaussian heat source is modified according to the law of laser energy reflection by powder, and a laser heat source model considering powder reflection is established. Then, the AM900 superalloy laser cladding model was established by using the fluid dynamics method with the modified Gaussian heat source and ordinary Gaussian heat source, respectively. The influence of the heat source model on the behavior of the laser cladding pool was studied. The thermal cycle curve was collected and the cladding layer morphology was obtained in the actual cladding process to verify the model. It is found that the impact of the droplet has the greatest impact on the flow pattern of the molten pool. The modified Gaussian heat source can reduce the peak temperature in the center of the molten pool (about 130 K), which can reflect the actual laser beam during cladding. The flow velocity of the molten metal simulated with the modified Gaussian heat source is slower than that of the ordinary Gaussian heat source, resulting in smaller melt pool width and penetration depth (reduced to 0.27 and 0.12, respectively). The improved heat source model is more in line with the actual cladding process.