Influence of Laser Power on Crack Evolution During Selective Laser Melting Manufacturing Process of Aluminum–Lithium Alloys

Aluminum–lithium alloys, as promising next-generation aerospace materials, exhibit outstanding properties, such as high strength, low density, excellent cryogenic performance, and superior corrosion resistance. In this study, aluminum–lithium alloy powders were processed via selective laser melting to systematically investigate the effects of processing parameters on manufacturing quality, microstructure, microhardness, residual stress, and tensile properties, with a particular emphasis on crack initiation and evolution. The results demonstrate that increasing laser power significantly improves specimen densification and reduces surface roughness. Moreover, the number of cracks decreases while their average length increases with elevated laser power. The maximum microhardness of 106.8 HV was achieved at the highest laser power, which also corresponded to the optimal tensile performance. These findings provide valuable insights into the relationship between laser parameters, microstructural evolution, and mechanical behavior, offering practical guidance for optimizing process parameters in the SLM fabrication of Al-Li alloy components for aerospace applications.