异种高强铝合金间搅拌摩擦焊接头组织与性能研究

Microstructure and Mechanical Properties of FSW Joints between Dissimilar High-strength Aluminum Alloys

通过搅拌摩擦焊接技术成功连接了两种应用于航天工业的铝合金2195-T8和2219-T87。实验中固定焊接转速,研究了焊缝组织和力学性能随焊接走速的变化关系,发现焊核区上部异种材料间有明显界面,且该界面形貌受焊接走速影响剧烈。同时在焊接速度较高时,发现一种新的搅拌摩擦焊接接头的断裂模式。此种断裂模式与焊核区上部形成的异种材料间界面形貌和冶金结合强度有关。本文探讨了其产生原因及其对接头力学性能的影响。

2195-T8 and 2219-T87, the two widely used high-strength aluminum alloys in aerospace industry, were successfully joined together by friction stir welding （ FSW）. The variation of microstructure and mechanical properties with different travel speeds was studied at a fixed tool rotation speed. Distinct interface was observed at the top part of weld nugget, and the morphology of this interface was influenced significantly by travel speed. Meanwhile, a new fracture mode of FSW joint was discovered at high travel speed. The fracture mode is related to the morphology and metallurgical bonding strength of the interface between dissimilar materials at the top part of weld nugget. The cause for this fracture mode and its effect on mechanical properties of the joints were investigated.