Study on the preparation process of ultrasonic-assisted friction stir diffusion welding of pure Zn/AZ61Mg alloy composite structure

This study successfully fabricated Zn/Mg composite structures using ultrasonic-assisted friction stir diffusion bonding (Ua-FSDB), systematically revealing the influence of ultrasonic vibration on the evolution of interfacial compounds and mechanical properties at the Zn-Mg bonding interface. The introduction of ultrasonic energy significantly modified the interfacial microstructure, transforming the bonding layer from a single Mg₂Zn₃ phase to a dual-layer structure consisting of an Mg₂Zn₃ sublayer and a composite region containing both Mg₇Zn₃ and MgZn phases. This microstructural optimization resulted in remarkable mechanical enhancement, with the tensile-shear strength increasing from 509 MPa to 898 MPa, representing a 76% improvement in joint performance.