不同加载应力下6061-T6铝合金挤压型材的疲劳断口研究  

Study on Fatigue Fracture of 6061-T6 Aluminum Alloy Extrusion Profile under Different Loading Stresses

作　　者：张颖 张大童[1] 邱诚[1] 张文[1] ZHANG Ying;ZHANG Datong;QIU Cheng;ZHANG Wen(National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学国家金属材料近净成形工程技术研究中心

出　　处：《热加工工艺》2018年第23期56-59,共4页Hot Working Technology

基　　金：广东省科技计划项目(2015B090926004)

摘　　要：对6061-T6铝合金挤压型材进行了轴向拉伸疲劳试验,在加载应力121~198MPa下测定其S-N(应力-循环次数)曲线,并对高应力(198MPa)和低应力(130MPa)下铝合金疲劳断口形貌特征进行分析。结果表明:6061-T6铝合金挤压型材疲劳寿命随加载应力增大而减小,其条件疲劳极限为127MPa。随着加载应力增大,疲劳裂纹萌生呈现多源性,疲劳裂纹扩展区面积减小,裂纹扩展第一阶段的裂纹偏转更加剧烈,疲劳条带宽度增加。The axial tensile fatigue test of 6061-T6 aluminum alloy extrudsion profile was carried out.The S-N (stress-cycletimes)curve was measured under the loading stress of 121-198 MPa,and the fatigue fracture morphologies of the aluminum alloy under high stress (198 MPa)and low stress (130 MPa)was analyzed.The results show that the fatigue life of the extrusion profile decreases with the increase of the loading stress,and the conditional fatigue limit is 127 MPa.With the increase of the loading stress,the fatigue crack initiation shows multi-source,the area of fatigue crack growth area decreases, the crack deflection in the first stage of crack growth is more intense,and the width of fatigue strip increases.

关 键 词：6061-T6铝合金 S-N(应力-循环次数)曲线 加载应力 疲劳断口 

分 类 号：TG379[金属学及工艺—金属压力加工] TG111.8