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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.
In this paper, the high cycle fatigue behavior of a new nickel-based superalloy DZ468 was studied.The results show that the fatigue strength of DZ468 alloy is 290 and 300 MPa respectively at 900 and 760 ℃ when the stress ratio is R = -1, The fracture of high-cycle fatigue specimen consists of fatigue source, fatigue zone and instantaneous zone.The crack initiation occurs on the surface, subsurface and internal defects, and the crack propagation has the first and second phases, and the crack propagation rate increases with the stress amplitude. There is a certain relationship between the mode of fatigue crack growth and the deformation mechanism of the smooth specimens. The combination of plane slip, cross slip and climb of the dislocations leads to two stages of crack growth at 900 and 760 ℃.