2A14-T6铝合金双轴肩搅拌摩擦焊特征及接头组织性能分析  

Characteristics and joint microstructure-property analysis of bobbin tool friction stir welding of 2A14-T6 aluminum alloy

作　　者：张会杰[1] 王敏[1] 张骁[1] 张景宝[1] 

机构地区：[1]中国科学院沈阳自动化研究所机器人学国家重点实验室,沈阳110016

出　　处：《焊接学报》2015年第12期65-68,104,共5页Transactions of The China Welding Institution

基　　金：国家科技重大专项"大型薄壁高精度搅拌摩擦焊设备技术研究"资助项目(2010ZX04007-011)

摘　　要：成功实现了2A14-T6高强铝合金的双轴肩搅拌摩擦焊,获得了表面成形良好,无内部缺陷的优质接头.试验发现,在焊缝的焊核内存在一个由上、下轴肩和搅拌针所驱动的材料塑性流动交汇区,该交汇区靠近焊缝下表面.微观分析表明,焊核上部的晶粒尺寸要小于其中部和下部的晶粒尺寸.焊缝各区的块状第二相在焊接中发生了溶解和粗化,导致接头内出现了宽度近乎轴肩直径二倍的软化区;焊缝各层硬度分布接近,没有出现常规搅拌摩擦焊中常见的接头各层异性现象.经拉伸测试证实,双轴肩焊接接头的强度系数达到了71%,拉伸时断在了焊核内的材料流动交汇区处.A 2A14-T6 aluminum alloy was successfully bobbin tool friction stir welded. The defect-free sound joint with good surface and inner formation was produced. It was found that a converging zone of material plastic flow,composed of upperand lower-shoulder-driven flows as well as pin-driven flow,was formed at the lower part of weld nugget zone. Microstructural a-nalysis indicated that the grain size of the upper part was smaller than that of the middle and lower parts in the weld nugget zone.A softening region,whose width was approximately twice that of the shoulder diameter,was formed in the joint due to the coarsening and dissolution of the block-shaped second phases. The hardness distributions of the three layers of the joint were nearly the same,indicating that the heterogeneity of joint properties commonly occurred in conventional friction stir welding was not present in bobbin tool friction stir welding. The tensile test results showed that the strength efficiency of the bobbin tool friction stir welded joint can reach 71%. The joint was fractured through the converging zone of material flow in the weld nugget zone.

关 键 词：高强铝合金 双轴肩搅拌摩擦焊 焊缝成形 微观组织 力学性能 

分 类 号：TG456.9[金属学及工艺—焊接]