放电能量对LA103Z/1060Al异种材料电磁脉冲焊接界面形貌的影响

Effect of Discharge Energy on Interface Morphology of LA103Z/1060Al Dissimilar Materials in Electromagnetic Pulse Welding

摘要:

采用电磁脉冲焊接实现了LA103Z和1060Al异种材料的连接，结合数值模拟和实验探究了放电能量对界面形貌的影响、波形的形成机制和界面元素扩散问题。结果表明：感应磁场和感应电流分别与焊接电流大小和变化速率相关。放电能量的提高增大了1060Al受到的洛伦兹力，提高了碰撞速度，而碰撞角度几乎不受影响。回弹现象改变了1060Al和LA103Z的接触状态，这是环形焊缝形成的关键。模拟和实际的界面形貌都为正弦波，且波幅从32 kJ的3.02 μm提高到了38 kJ的6.48 μm。波形的形成源于界面上剪切作用及碰撞引发的剪切不稳定性和金属塑性流动共同作用。界面上没有观察到熔化现象，接头最大剪切强度达到了铝母材的90.38%。模拟结果表明界面上的温度始终低于母材的熔点是接头力学性能提高的关键。

Abstract:

The connections of dissimilar materials LA103Z magnesium-lithium alloy and 1060Al alloy were achieved by electromagnetic pulse welding (EMPW). The effects of discharge energy on interface morphology, wave formation mechanisms, and element diffusion were systematically investigated through numerical simulations and experiments. The results indicate that the induced magnetic field and current are determined by the welding current's magnitude and rate of change, respectively. The increase in discharge energy enhances the Lorentz force experienced by 1060Al, thereby increasing the impact velocity, while the impact angle almost remains unaffected. The rebound phenomenon, which alters the contact state between the flyer plate and the target plate, is identified as the key factor in forming the annular weld seam. Both the simulated and actual interface morphologies are sinusoidal, with the amplitude increasing from 3.02 μm at 32 kJ to 6.48 μm at 38 kJ. The wave formation is attributed to shear-induced instability and metal-plastic flow triggered by high-speed collision. No melting is observed at the interface. The maximum shear strength of the joint reaches 90.38% of that of the aluminum base material. Numerical simulations confirm that the interface temperature remains below the melting points of both base materials, which is critical for improving the mechanical performance of the joint.