中国科学院力学研究所机构知识库

It is generally believed that the crack defect is the fatal issue that restricts the development of additive manufacturing technology. In this paper, Ni60 alloy coating on H13 surface is manufactured by laser cladding, and the dynamic evolution behavior of cracks during the process of single-track and multi-track overlapping cladding is studied. The morphology and microstructure characteristics of the coating and the crack initiation and propagation behavior are analyzed. The results show that the cracks mainly originate from the surface of the clad and propagate along the depth direction to the substrate. The laser power and scanning speed are the main factors that affect the crack behavior. With the increase of laser power, the process range for crack-free cladding is expanded. When the cladding speed is relatively low, the crack in the substrate can be initiated, and the crack propagates in the direction parallel to the laser scanning speed, which is manifested as the substrate being torn. The transverse cracks and the network-shaped cracks propagate continuously from single-track to multi-track cladding process. The crack-free cladding process can be achieved by a reasonable selection of processing parameters. This work aims to deeply understand the dynamic evolution behavior of cracks in laser additive manufacturing, and thus provide theoretical guidance for the crack-free cladding process.