镍基单晶高温合金蠕变-疲劳寿命评估方法进展

论述镍基单晶合金的滑移变形机制和疲劳裂纹萌生机理，分别介绍镍基单晶合金蠕变寿命和低循环疲劳寿命分析评估模型；镍基单晶合金蠕变、疲劳寿命的研究方法可分为应用各向异性张量描述非弹性各向异性变形的宏观力学(唯象)模型和基于晶体学滑移变形理论的微观力学模型；晶体取向、平均应力、环境温度、循环频率、循环应力比是影响单晶合金蠕变-疲劳寿命的主要因素。复杂应力状态下的单晶合金多轴低循环疲劳损伤，单晶合金在疲劳-蠕变交互作用下的疲劳损伤和单晶合金的接触疲劳损伤等问题是需要研究的重要课题。

DEVELOPMENT ON EVALUATING METHOD OF CREEP-FATIGUE LIFE OF SINGLE CRYSTAL NICKEL-BASED SUPERALLOYS

After discussing the mechanisms of deformation and fatigue crack initiation of single crystal Nickel based superalloys, the approaches and models for evaluating creep life and low cyclic fatigue life of single crystal Nickel based superalloys were introduced. Two approaches are being developed and evaluated for the single crystal materials: a macroscopic model that employs anisotropic tensors to model inelastic deformation anisotropy, and a microscopic model based on crystallographic slip systems. The crystallographic orientation, mean stress, environmental temperature, cyclic frequency and cyclic ratio of stress are main factors to affect creep fatigue life of single crystal Nickel based superalloys. Multiaxial low cycle fatigue damage under complex stress states, fatigue damage caused by fatigue creep interaction and fretting fatigue failure of single crystal Nickel based superalloys are important problems into which are needed to research.