铜/钛搅拌摩擦搭焊接头特征及界面结合机制

Interface Characteristic and Connectionism of Friction Stir Welding Lap Joints of Cu/Ti Dissimilar Alloys

摘要:

研究了搅拌摩擦焊法搭接TA2工业纯钛和T2紫铜。工艺优化实验结果表明：Cu/Ti搭接搅拌摩擦焊工艺窗口较窄，在搅拌头转速800 r/min、焊速20 mm/min以及搅拌头转速900 r/min、焊接速度30 mm/min的焊接工艺参数配比条件下，可获得无缺陷且焊缝表面、搭接界面成形良好的Cu/Ti接头。对搅拌头转速800 r/min、焊速20 mm/min的焊接参数下获得的Cu/Ti接头焊缝进行金相和SEM观察，分析结果表明：搭接界面两侧Cu、Ti宏观流动现象明显，Ti向Cu一侧的塑性材料流动量要明显优于Cu向Ti一侧，且在局部机械混合区呈典型的Cu/Ti相间条带状结构；在搭接界面处形成一层平均厚度约为4.8 μm的扩散过渡层，在过渡层中Cu的扩散速度要大于Ti的扩散速度，Cu/Ti搭接界面形成冶金结合

Abstract:

The lap joint of commercial purity titanium (TA2) and copper (T2) plates was made via friction stir welding technique. Based on the optimization experiments, the suitable process parameters have been obtained as follows: rotation speed of 800rpm, travel speed of 20 mm/min and rotation speed of 900 r/min, travel speed of 30 mm/min. Under this process conditions, the defect-free lap welds with well formed surface and the interface of joint can be obtained. Using OM and SEM the investigation on the weld characteristics was conducted. Results show that the phenomenon of the flow in the macro scale of Cu and Ti between the joint-interface is exhibited obviously, and the flow amount of Ti to Cu is more than that of Cu to Ti greatly, furthermore, some parts of joint-interface present the typical bounded texture microstructure of Cu and Ti. About 4.8 μm thickness of diffused intermediate layer is formed in the interface of lap joint, the diffusion velocity of Cu is faster than that of Ti, and the lap joint of Cu and Ti has formed the metallurgical bonding