晶体取向的偏差和随机性对镍基单晶叶片强度与蠕变寿命的影响

Influence of Deviation and Randomness of Crystallographic Orientations on the Strength and Life of Nickel-Base Single Crystal Superalloy Turbine Blades

本文提出双参数蠕变损伤模型用以模拟镍基单晶合金叶片的强度和寿命。该模型得到单轴应力状态和模拟叶片、双剪切试样复杂应力状态的考核。叶片分析表明:单晶叶片轴向的偏角增大,强度的分散性变大。两个不受控的晶体取向变化时,滑移系的分切应力最大有15%的变化;轴向的偏角的增大,寿命的分散性变大,15°的偏角,寿命偏差6倍。两个不受控的晶体取向变化时,寿命有50%的变化。结果表明:对叶片进行3维取向优化,可以提高叶片的蠕变寿命。

A twodamagevariable creep constitutive model has been presented for the strength and life of nickelbase single crystal superalloy turbine blades.Uniaxial creep experiments for different orientations and stress levels have been conducted and validated for the model parameters.Modeling creep blades and double shear creep specimens were tested experimentally.The model has been validated by the uniaxial stress state and multiaxial stress state specimens.With the increase in deviation of the axial crystallographic orientations of the blade,the deviation of the strength increases,by the name of resolved shear stress of the slip systems.The randomness of the two uncontrolled crystallographic orientations of the blades results in a 15% deviation of the strength.The life deviation increases with the increasing deviation of axial crystallographic orientation.If there is a 15° deviation of the axial orientation,the life will have a deviation of factor 6.The randomness of the two uncontrolled orientations reduces 50% deviation of life.The study shows that the blade crystallographic orientations should be optimized for a better conjunction of strength and creep life.