Cross-scale modeling and experimental research on the ultrahigh-speed laser cladding process of aluminum bronze

Ultrahigh-speed laser cladding is an emerging surface modification technology that has higher cladding efficiency and better coating quality compared with traditional laser cladding technology. Due to the characteristics of the aluminum-bronze ultrahigh-speed cladding process, such as a small molten pool volume, a large temperature gradient, and extremely strong temporality, it is difficult to dynamically track and reveal the coupled evolution behavior of multiple physical fields through experimental methods. Therefore, a coupling model of temperature and flow field in the ultrahigh-speed laser cladding process of aluminum-bronze powder was established in this paper. The instantaneous evolution laws of the temperature field and flow field were calculated and revealed. Based on the results of macroscopic coupling calculations, a numerical model for the growth of dendrites during the solidification of the molten pool was established using the phase field method, providing a quantitative understanding of the dendrite growth behavior during the solidification process of ultrahigh-speed laser cladding of aluminum bronze. Friction wear test and dendrite test were carried out on the coated specimens, and the morphology of the microstructure was observed by an optical microscope. This study shows that a nearly rectangular light spot was formed, with the hottest area located slightly behind the centerline; the maximum flow velocity of the molten pool was 0.496 m/s. Under the influence of circulation, the equiaxed crystals and dendritic crystals in the pastelike zone grow more rapidly on the side facing the flow.