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采用疲劳试验机对3种不同对接工艺的Al-Li-S4铝锂合金FSW对接接头及母材进行了疲劳性能测试,并采用光学显微镜和扫描电镜对组织和断口进行了分析。结果表明:在210MPa应力水平下,Al-Li-S4-T8铝锂合金母材在疲劳寿命达到200万次;在600/400、800/80、800/2003种典型FSW工艺条件下,800/200参数接头疲劳性能最优,在170MPa应力水平下,接头疲劳寿命可达200万次;Al-Li-S4合金FSW接头疲劳断裂大部分从焊缝表面起裂,这可能与FSW过程中金属材料的周期性流动和周期性微观组织使焊缝内部出现强度薄弱区或应力集中有关。
The fatigue properties of Al-Li-S4 Al-Li alloy FSW butt joint and base metal of 3 different butt-joining processes were tested by fatigue tester. The microstructure and fracture surface were analyzed by optical microscope and scanning electron microscope. The results show that the fatigue life of Al-Li-S4-T8 Al-Li alloy base metal reaches 2000000 times under the stress of 210MPa. Under the typical FSW conditions of 600/400, 800/80 and 800/2003, 200 joint fatigue life is optimal, the fatigue life of joints can reach 2000000 times at the stress level of 170MPa; Most of the fatigue fracture of Al-Li-S4 alloy FSW joints rupture from the surface of the weld, which may be related to the metal material The periodic flow and periodic microstructure cause the weld to appear in the weak area or stress concentration.