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根据循环损伤累积的思想,发展了一种基于临界平面的镍基单晶高温合金疲劳寿命预测模型.以非弹性应变能密度最大的滑移面作为镍基单晶高温合金承受最大损伤的临界平面,并结合基于滑移系的黏塑性变形分析结果,建立了疲劳寿命与最大滑移系分解剪应力、最大滑移剪应变率、滑移剪应变范围、应变比以及拉伸/压缩保载频率等临界平面参数的函数关系.采用760℃下DD6单晶的疲劳试验结果对上述预测模型进行验证,试验与计算结果符合良好,基本在2倍分散带内.
Based on the idea of cyclic damage accumulation, a prediction model of fatigue life of Ni-based single crystal superalloy based on the critical plane has been developed.As the critical plane of maximum damage of Ni-based single crystal superalloy, the slip surface with the highest inelastic strain energy density , And combined with the results of visco-plastic deformation analysis based on slip system, the relationship between fatigue life and maximum shear stress, maximum slip shear strain rate, slip shear strain range, strain ratio and tensile / compression loading frequency And other critical plane parameters.According to the fatigue test results of DD6 single crystal at 760 ℃, the above prediction model is validated, and the experimental and calculated results are in good agreement with the experimental data.