Microstructure evolution characterization of Ni-based GH4720Li superalloy during strain-controlled fatigue at 550℃
作者机构：Gaona Aero Material Co.Ltd.Beijing 100081China High Temperature Materials Research InstituteCentral Iron and Steel Research InstituteBeijing 100081China
出 版 物：《Journal of Iron and Steel Research International》 (Journal of Iron and Steel Research, International)
年 卷 期：2021年第28卷第7期
页 面：901-909页
核心收录：
学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）]
主 题：Ni-based superalloy High-temperature fatigue Transmission electron microscopy Scanning transmission electron microscopy Fatigue crack tip Oxide
摘 要：High-temperature fatigue property of Ni-based GH4720Li superalloy at 550℃has been investigated at maximum strain from 0.8%to 1.1%.Microstructural characterization and oxidation behavior of superalloy during high-temperature fatigue have been analyzed by transmission electron microscopy and scanning transmission electron *** results show that a stable response following a slight cyclic hardening during initial cycles was revealed at the maximum strain from 0.8%to 1.0%.The stable response decreased with an increase in maximum *** cyclic hardening was observed at the maximum strain of 1.1%.There is difference in dislocation substructures between primary γ precipitates and γ *** cell and mechanical twin were formed in the interior of primary γ precipitates and γ *** primary γ precipitate interface would migrate toward the interior of primary γ precipitates along twin boundaries,leading to instability of primary γ *** secondary γ depleted zone was distinctly generated near the surface due to the decomposi-tion of secondary γ *** crack initiation and propagation during high-temperature fatigue were found inside the secondary γ depleted *** primary γ precipitates could effectively hinder the crack ***-rich oxide films(Al_(2)O_(3))were initially produced at crack tips,because the rate of diffusion of Al was relatively higher than that of other elements at crack tips.
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