Application of Ultrasonic Vibration Assistance in Laser Welding Ultrasonic vibration-assisted laser welding (UVA-LW) integrates high-frequency ultrasound with laser welding to regulate molten pool flow, promote degassing, refine grains, and release residual stress, effectively resolving long-standing issues such as porosity, cracking, and brittle intermetallic compounds. This acousto-optic synergy significantly enhances weld morphology, strength, ductility, and the reliability of dissimilar-metal joints. With broad potential in power batteries, aerospace, and precision manufacturing, UVA-LW is emerging as a next-generation enhancement technology for high-performance material joining.