采用双轴肩搅拌摩擦焊对4 mm厚6056铝合金进行了焊接，分析了接头不同特征区的显微组织和力学性能的非均匀特性. 结果表明，接头横截面等效应变呈哑铃状，与焊缝横截面宏观形貌一致；接头横截面沿焊缝中心左右两侧塑性应变呈非对称分布状态，其中接头前进侧的塑性应变值高于后退侧；搅拌区靠近前进侧和中间位置的大角度晶界比例高于后退侧，前进侧和中间位置主要为B型$\{1 \overline 1{2}\}$<110>织构，后退侧为A型$\{11 \overline{1}\}$<110>织构；焊缝的带状区局部发生不完全动态再结晶，变形晶粒比例高达58.9%，带状区为B型$\{11 \overline {2}\}$<110>织构，织构强度为10.6，高于搅拌区其它位置；接头热影响区的应变超过18%，高于整体接头应变3.6%，热力影响区的应变与整体接头相近，而搅拌区的应变小于整体接头.
6056 aluminum alloy with 4mm thickness was welded by bobbin tool friction stir welding, and the non-uniform characteristics of microstructure and mechanical properties of different characteristic areas of the joint were studied. Results show that the equivalent strain of the cross section of the joint is dumbbell shape, which is consistent with the macro-morphology of the cross section of the weld. The plastic strain distribution along the left and right sides of the weld center is asymmetrical, and the plastic strain value at the advancing side of the joint is higher than that at the retreating side. The proportion of high angle grain boundary near the advancing side and the middle side is higher than that on the retreating side. The advancing side and middle side are mainly B-type $\{1 \overline 1{2}\} $<110> texture, and the retreating side is A-type $\{11 \overline{1}\} $<110> texture. Incomplete dynamic recrystallization occurs in the band pattern area of the weld, and the proportion of deformed grains is 58.9%. The band pattern area is B-type $\{11 \overline {2}\} $<110> texture with texture strength of 10.6, which is higher than that of other positions in the stir zone. The strain in the heat affected zone is more than 18%, which is higher than the whole joint with 3.6%. The strain in the thermo-mechanically affected zone is similar to that of the whole joint, while the strain in the stir zone is less than that of the whole joint.
[1] 温泉, 李文亚, 吴雪猛, 等. 单静止上轴肩BT-FSW工艺过程及成形机理[J]. 焊接学报, 2022, 43(7): 88-96
Wen Quan, Li Wenya, Wu Xuemeng, et al. Forming mechanism and processing of stationary upper shoulder BT-FSW[J]. Transactions of the China Welding Institution, 2022, 43(7): 88-96
[2] 刘会杰, 高一嵩, 张全胜, 等. 2A14-T4铝合金厚板搅拌摩擦焊接头微观组织和力学性能[J]. 焊接学报, 2022, 43(6): 20-24
Liu Huijie, Gao Yisong, Zhang Quansheng, et al. Microstructure and mechanical properties of friction stir welded joint of 2A14-T4 aluminum alloy thick plate[J]. Transactions of the China Welding Institution, 2022, 43(6): 20-24
[3] 吉华, 邓运来, 邓建峰, 等. 焊接速度对6005A-T6铝合金双轴肩搅拌摩擦焊接头力学性能的影响[J]. 焊接学报, 2019, 40(5): 24-29
Ji Hua, Deng Yunlai, Deng Jianfeng, et al. Effect of welding speed on mechanical properties of bobbin tool friction stir welded 6005A-T6 aluminum alloy joints[J]. Transactions of the China Welding Institution, 2019, 40(5): 24-29
[4] Wen Q, Li W Y, Patel V, et al. Investigation on the effects of welding speed on bobbin tool friction stir welding of 2219 aluminum alloy[J]. Metals and Materials International, 2020, 26(12): 1830-1840.
[5] Wang F F, Li W Y, Shen J J, et al. Effect of tool rotational speed on the microstructure and mechanical properties of bobbin tool friction stir welding of Al–Li alloy[J]. Materials & Design, 2015, 86(5): 933-940.
[6] 王磊, 付强, 安金岚, 等. 2A12-T4 铝合金搅拌摩擦焊多区域疲劳裂纹扩展行为[J]. 焊接学报, 2021, 42(2): 24-29
Wang Lei, Fu Qiang, An Jinlan, et al. Multi-zone fatigue crack growth behavior of friction stir welding of 2A12-T4 aluminum alloy[J]. Transactions of the China Welding Institution, 2021, 42(2): 24-29
[7] 刘西畅, 李文亚, 高彦军, 等. 铝合金双轴肩搅拌摩擦焊过程材料流动行为[J]. 焊接学报, 2021, 42(3): 48-56
Liu Xichang, Li Wenya, Gao Yanjun, et al. Material flow behavior during bobbin-tool friction stir welding of aluminum alloy[J]. Transactions of the China Welding Institution, 2021, 42(3): 48-56
[8] Olea C A W, Roldo L, Dos Santos J F, et al. A sub-structural analysis of friction stir welded joints in an AA6056 Al-alloy in T4 and T6 temper conditions[J]. Materials Science and Engineering: A, 2007, 454−455: 52−62.
[9] 邓永芳, 左敦稳, 宋波. 搅拌摩擦焊接偏心挤压流动模型[J]. 焊接学报, 2013, 34(12): 41-45
Deng Yongfang, Zuo Dunwen, Song Bo. Eccentric extrusion flow model of friction stir welding[J]. Transactions of the China Welding Institution, 2013, 34(12): 41-45
[10] 张昭, 刘亚丽, 张洪武. 轴向载荷变化对搅拌摩擦焊接过程中材料变形和温度分布的影响[J]. 金属学报, 2007, 43(8): 868-874
Zhang Zhao, Liu Yali, Zhang Hongwu. Effect of variation of axial load on material deformations and temperature distributions in friction stir welding[J]. Acta Metallurgica Sinica, 2007, 43(8): 868-874
[11] 孟杨, 任群, 鞠新华. 利用局域取向差衡量变形金属中的位错密度[J]. 材料热处理学报, 2014, 35(11): 122-128
Meng Yang, Ren Qun, Ju Xinhua. Evaluation of dislocation density by local grain misorientation in deformed metals[J]. Transactions of Materials and Heat Treatment, 2014, 35(11): 122-128
[12] 张志函. AA2024 搅拌摩擦焊接头局部-全局力学性能研究[D]. 西安: 西北工业大学, 2016.
Zhang Zhihan. Study on local and global mechanical properties of friction stir welded AA2024 alloy joints[D]. Xi’an: Northwestern Polytechnical University, 2016.
