7050T7451和7150T7751铝合金疲劳强度研究

Study on fatigue strength of 7050T7451 and 7150T7751 aluminum alloys

航空用铝合金结构材料疲劳破坏时有发生,研究材料在交变应力下的疲劳特性具有非常重要的意义。采用成组法和升降法对7050T7451铝合金板材进行高周疲劳试验,获得P-S-N曲线,并用7150T7751铝合金进行试验,在较少样品数量下获得疲劳强度和S-N曲线。结果表明:应力比为0时,7050T7451铝合金疲劳强度为268 MPa,使用三参数幂函数可获得较好的P-S-N曲线拟合效果;7150T7751铝合金疲劳强度为280 MPa,S-N曲线应力S与对数寿命lgN存在线性关系。

Fatigue failure often occurs in aluminum alloy structural materials used in aviation,and studying the fatigue characteristics of materials under alternating stress is of great significance.High cycle fatigue test of 7050T7451 aluminum alloy plate was conducted by in-group method and up-and-down method,so that P-S-N curve was obtained.And 7150T7751 aluminum alloy was used for the test to obtain fatigue limit and S-N curve under a small number of specimens.The results show that when the stress ratio is 0,the fatigue limit of 7050T7451 aluminum alloy is 268 MPa,and good P-S-N curve fitting effect can be obtained using three-parameter power function;the fatigue limit of 7150T7751 aluminum alloy is 280 MPa,and there is a linear relationship between stress S and log life lgN in S-N curve.