Effect of number of adjusting times on fatigue properties of FSW joint of 6082-T6 aluminum alloy

LIU Guotian; DUAN Zebin; LIU Kai; CHEN Haikuan; LI Yongyin

doi:10.7512/j.issn.1001-2303.2021.11.10

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Effect of number of adjusting times on fatigue properties of FSW joint of 6082-T6 aluminum alloy
Vol. 51, Issue 11, Pages: 56-59(2021)
DOI： 10.7512/j.issn.1001-2303.2021.11.10

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LIU Guotian, DUAN Zebin, LIU Kai, et al. Effect of number of adjusting times on fatigue properties of FSW joint of 6082-T6 aluminum alloy. [J]. 51(11):56-59(2021)
DOI：

LIU Guotian, DUAN Zebin, LIU Kai, et al. Effect of number of adjusting times on fatigue properties of FSW joint of 6082-T6 aluminum alloy. [J]. 51(11):56-59(2021) DOI： 10.7512/j.issn.1001-2303.2021.11.10.

摘要

平头搅拌针调修是指在原有焊缝背面用无搅拌针的搅拌头对焊缝再次进行搅拌摩擦焊,使焊缝温度升高,改善FSW接头性能。对平头搅拌针不同调修次数的高速列车用6082-T6铝合金搅拌摩擦焊接头进行脉动拉伸疲劳试验,利用扫描电镜观察分析疲劳断口,试验结果表明:铝合金搅拌摩擦焊接头指定寿命为1×107次的中值疲劳极限随着搅拌针调修次数的增加而升高。平头搅拌针调修两次时焊接接头的疲劳极限强度较高,焊缝背面边缘是本次试验集中产生裂纹的部位。启裂区和扩展区疲劳纹清晰;终断区为深韧窝状花样的韧性断口。

Abstract

Through pulsating tensile fatigue test, the friction stir welding（FSW） joints of 6082-T6 aluminum alloy used for high speed train were studied with different number of adjusting times by the flat stir pin, and the fatigue fractures were observed and analyzed by SEM. The results show that the specified life of FSW joints of aluminum alloy is median value fatigue limit strength of 1 ×107, which rises as the number of adjusting times increases. The welded joints have higher fatigue limit strength with twice adjusting by flat stir pin, and the cracks are mainly concentrated at the back edge of the welds. The fatigue cracks in the crack initiation zone and extension zone are vivid, and the final broken zone is the ductile fracture with deep dimple pattern.