镍基铸造高温合金低周疲劳研究进展:影响因素、变形机理及寿命预测

Recent Progress in Low Cycle Fatigue of Cast Nickel-Base Superalloy:Influencing Factors,Deformation Mechanism and Life Prediction

镍基铸造高温合金具有优异的高温性能,广泛应用于航空发动机涡轮叶片等热端部件之中。航空发动机涡轮叶片是发动机中工作环境最为恶劣、结构最为复杂的零件之一,在发动机运行过程中所产生的高温交变应力的作用下,合金承受着严重的应力、应变循环损伤,裂纹往往在合金中的薄弱区域形成并扩展,使合金以低周疲劳的模式失效,严重影响了合金的服役寿命,因此对合金低周疲劳性能的研究尤为重要。本文详细阐述了影响镍基铸造高温合金低周疲劳性能的表面缺陷、内部组织及缺陷、晶体取向和低周疲劳试验条件等四方面因素,从位错运动方式和形态变化特点出发,研究了不同温度下镍基铸造合金的变形机制,最后总结了合金低周疲劳寿命预测的应力应变准则、能量准则、损伤累积准则及临界面和临界距离准则。

Cast nickel-base superalloys are widely used in hot end components such as turbine blades of aeroengines because of their excellent high temperature performance.Aeroengine turbine blade is one of the parts with the worst working environment and the most complicated structure.The alloy bears serious stress and strain cycle damage under the action of high temperature alternating stress produced during engine operation.And cracks often initiate and further develop in these weak areas,resulting in low cycle fatigue failure of the alloy,which seriously affects the service life of the alloy.Therefore,the research on the fatigue performance of the alloy is particularly important.In this paper,four factors affecting the low cycle fatigue properties of cast nickel-base superalloy were described in detail,including surface defects,internal structure and defects,crystal orientation and test conditions.Based on the characteristics of dislocation movement mode and morphology,the deformation mechanism of cast nickel-base superalloy at different temperatures was studied.Finally,the prediction methods of low cycle fatigue life were summarized.