DZ468合金高周疲劳性能研究

来源期刊：金属学报2010年第6期

论文作者：刘恩泽 郑志 佟健 宁礼奎 管秀荣

文章页码：708 - 714

关键词：镍基高温合金； 高周疲劳性能； 断口

Key words：Ni-based superalloy； high cycle fatigue property； fracture

摘    要：本文研究了新型镍基高温合金DZ468的高周疲劳性能.结果表明:当应力比R=-1时,在900和760℃条件下,DZ468合金的疲劳强度分别为290和300 MPa.DZ468合金的高周疲劳试样断口由疲劳源、疲劳区和瞬断区组成.裂纹在表面、次表面和内部缺陷部位萌生,裂纹扩展具有第Ⅰ和第Ⅱ阶段,随应力幅增加裂纹扩展速率增大.光滑试样的疲劳裂纹扩展方式与变形机制间存在一定的关系,位错的平面滑移、交滑移和攀移的共同作用导致了合金在900和760℃时裂纹扩展具有两个阶段.

Abstract: The high cycle fatigue properties of a new type Ni-based superalloy DZ468 were investigated in this paper.The high cycle fatigue strengths of DZ468 alloy at 900 and 760℃ with a ratio of stress R=-1 reach 290 and 300 MPa,respectively.The high cycle fatigue fractures of DZ468 alloy were composed of fatigue source,fatigue district and final stage.Cracks originate from surface, sub-surface and inner defect of sample.At 900 and 760℃,stageⅠand stageⅡcrack propagation could be observed from fatigue fracture,which was caused by the combination action of planar slip, cross slip and climb of dislocations.With increasing of stress value,the crack propagation rate quickly increase.A correlation exists between the crack propagation mode and deformation mode.