Low cycle fatigue of a single crystal CoNi-base superalloy

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:827

Article

Murray, Sean P.¹  Cervellon, Alice¹  Cormier, Jonathan²  Pollock, Tresa M.¹ 

[1] Univ Calif Santa Barbara, Mat Dept, Santa Barbara, CA 93106 USA

[2] Univ Poitiers, CNRS, UPR 3346, Inst Pprime,ENSMA,Dept Phys & Mech Mat,ISAE, Teleport 2,1 Ave Clement Ader,BP 40109, F-86961 Futuroscope, France

关键词: Superalloys;    Low cycle fatigue;    Oxidation;    Electron microscopy;   

DOI  :  10.1016/j.msea.2021.142007

来源: Elsevier

【 摘 要 】

The low cycle fatigue response of a single crystal gamma'-containing CoNi-base superalloy has been investigated in air and in vacuum at 950 degrees C. The fatigue performance is demonstrated to be similar to the 1st-generation single crystal Ni-base superalloy AM1. Fracture surface imaging and cross-sections on both alloys reveal that oxidation-assisted surface cracking is responsible for fatigue crack initiation in air. The fatigue performance improves under vacuum for both alloys as crack initiation transitions to internal casting pores retained from the solidification process. Recrystallized regions on the fracture surfaces of the vacuum-tested samples of both alloys are identified by electron backscattered diffraction, which has not been previously reported for single crystal Ni-base alloys at these test conditions. The role of the base element (Ni-vs. CoNi-vs. Co-base) on the fatigue performance is discussed.

【 授权许可】

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