在室温下对5083H111轧制铝合金板三个典型方向——轧制方向(RD方向)、与轧制方向成45°角方向(MD方向)、垂直于轧制方向(TD方向)的试样进行了单轴对称应变控制的低调疲劳试验,研究了不同方向试样的循环变形行为和疲劳寿命差异。结果表明:铝合金板在三个方向上都表现出了明显的循环硬化特性,即在恒定的应变幅下,三个方向的响应应力幅均随着循环次数的增加而增大,并且外加应变幅越大,响应应力幅也越大;三个方向的低周疲劳ε-Nf曲线差别不明显;三参数幂函数寿命模型可以很好地预测5083H111铝合金的低周疲劳寿命。

Uniaxial symmetrical strain-controlled fatigue tests were conducted at room temperature for rolled aluminum alloy plates along three typical directions,the rolling direction (RD),the direction at 45° angle with the rolling direction (MD),and the transverse direction (TD),to study the differences of cyclic deformation and fatigue lives of the 5083H111 alloy plates. The results show that the rolled alloy plates were characterized by obvious cyclic hardening in three directions-that was to say the responded stress amplitude increased progressively with the increase of the cycles number. The larger the applied strain amplitudes,the larger the responded stress amplitudes. However,the differences among the ε-Nf curves in three directions were not obvious. The fatigue lives of the alloy plates were predicted by a three-parameter power function failure model,and the predicted lives were in good agreement with the experimental ones.