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基于高周疲劳弯曲实验,研究了航空用铝合金板材Al7475-T3的各向异性疲劳行为.结果表明:轧制后形成了扁平长条状结构的7475-T3铝合金具有良好的耐疲劳损伤性能.在室温弯曲加载条件下,从3个平面(S-T,S-L,T-L)截取的光滑试样的疲劳极限最高可达200 MPa,除在T-L面上表现为各向同性外,其余两面的疲劳性能均表现出各向异性.采用以最弱链接理论为基础的概率疲劳准则,分析了铝合金板材中疲劳裂纹产生的可能性,但模拟结果与实际相差较远.综合考虑晶粒有效滑移长度和夹杂物尺寸两因素,对疲劳极限的影响进行模型计算,得出的Kitagawa曲线与实际情况比较吻合.
Based on the high-cycle fatigue bending test, the anisotropic fatigue behavior of aluminum alloy sheet Al7475-T3 was studied. The results show that the 7475-T3 aluminum alloy with flat and long strip shape after rolling has good fatigue resistance Under the condition of room temperature bending loading, the fatigue limit of the smooth specimen intercepted from three planes (ST, SL, TL) can reach up to 200 MPa. Except for the isotropic behavior on the TL surface, the fatigue properties of the other two surfaces Both show the anisotropy.Using the probability fatigue criterion based on the weakest link theory, the possibility of fatigue crack in the aluminum alloy sheet is analyzed, but the simulation result is far from the actual.Considering the effective slip length And inclusion size of two factors, the impact of fatigue limit model calculations, the Kitagawa curve obtained and the actual situation more in line.