2219-T6激光同轴辅助搅拌摩擦焊性能与组织分析

对2219-T6铝合金激光同轴辅助搅拌摩擦焊接头的宏观形貌、力学性能及显微组织进行了研究.结果表明，激光辅助热源的加入有助于消除金属塑性流动不充分引起的隧道缺陷，提升接头性能，但激光功率过大会加剧焊缝软化而使性能下降.激光辅助热源使焊核区扩大，且焊核区中θ相（Al₂Cu）增大，但对热力影响区的显微组织无明显影响.通过固溶+人工时效方法的焊后热处理以显著提升接头强度（从母材强度的76%提升100%）.加入激光的焊核区及热力影响区在热处理后晶粒尺寸相比不加入激光有所减小，且激光功率越大，对应的晶粒尺寸越小.

Mechanical properties and microstructures of laser coaxially assisted friction stir welded 2219-T6 aluminum alloy

Laser coaxially assisted friction stir welding process of 2219-T6 aluminum alloy was investigated, concentrating on weld appearance, mechanical properties and microstructure characteristics of the joints. The results show that assisted laser heat can effectively prevent tunnel defect, thus improving joint performance. However, high laser power increases softening of the welded zone and decreases joint performance. Assisted laser heat enlarges the nugget zone (NZ) and increases the size of θ phase (Al₂Cu), but has no obvious effect on microstructures of thermo-mechanically affected zone(TMAZ). T6 heat treatment of the welded joints can obviously increase the joint strength (from 76% of base metal to 100%). The grain sizes in NZ and TMAZ of joints with assisted laser heat are smaller than those without assisted laser after heat treatment.