Simulation and Experimental Analysis of Different Interlayers in Cu-Mg Ultrasonic Welding

This study investigates the impact of different interlayers (such as Mg, Zn and Ni) on welding performance of Cu-Mg dissimilar metal joints, combining simulation and experimental approaches. Initial simulations were conducted to evaluate the effects of Mg, Zn and Ni interlayers on the bonding behavior and mechanical properties of Cu-Mg sheets. Based on simulation results, Ni interlayer welding was selected for experimental validation where optimized welding parameters (heat input of 1.5 kJ/mm, welding speed of 100 mm/s, clamping force of 4 MPa and frequency of 20 kHz) were applied. After tensile testing, SEM analysis of welded joints subjected to higher applied loads (sample (S4 = 5667 N)) which exhibited smoother interfaces and more uniform diffusion. However, lower-strength samples (S5 = 5293 N) showed localized microvoids and inconsistent bonding. SEM–EDS line scan analysis of two welded samples revealed that the S1 shows higher Ni (14.64 wt%) and lower Cu (39.44 wt%) content compared to S2, indicating better Ni diffusion and bonding quality. The variations align with SEM and tensile test results, highlighting the importance of Ni interlayer diffusion for joint strength. The experimental results confirmed that the Ni interlayer welded joints exhibited up to 40% higher tensile strength and better interfacial bonding in the welded joints. This study provides valuable insights into optimization of interlayer materials and welding parameters for producing high-strength, reliable Cu-Mg joints, particularly for demanding applications in aerospace and automotive industries.