摘要
γ′和γ′′相是镍基高温合金中的重要强化相,为了阐明其在热处理中的析出演化机制,本工作以广泛使用的GH4169合金为对象,采用小角中子散射原位研究了固溶时效热处理中第二相的析出演化行为,并借助TEM对非原位样品进行验证分析。结果表明:合金中第二相主要在时效过程中析出,包括球状γ′相和γ′与γ′′复合相(以γ′′/γ′/γ′′三明治结构为主)。其中,球状γ′相数量随时效进行不断增多;复合相在一级时效中大量形成,但在二级时效中数量变化不大。此外,2类析出相尺寸均在一级时效时逐渐增大,在二级时效时几乎不变。在整个时效过程中,球状γ′相与基体相界面逐渐尖锐,而复合相越来越扁,其界面成分波动始终显著。由此可知,第二相的析出演化行为受控于界面元素扩散机制。
Theγ′andγ′′phases are crucial strengthening components in Ni-based superalloys.Understanding their precipitation and evolution mechanism during heat treatment is essential for tailoring the mechanical properties of the superalloys.Herein,GH4169 superalloy was used to investigate the precipitation and evolution behaviors of secondary phases during in situ standard heat treatment by time-of-flight small-angle neutron scattering.Further,transmission electron microscopy was employed to observe the secondary phases generated in samples after ex situ heat treatment.Results showed that the secondary phases,including the sphericalγ′phase and coprecipitates(mainly theγ′′/γ′/γ′′sandwich structure),mostly occurred during the aging treatment.After the formation of coprecipitates during the first aging treatment(AT1),their quantity apparently remained stable during the second aging treatment(AT2).Furthermore,the average size of theγ′phase and coprecipitates gradually increased during the AT1 stage while remaining almost constant during the AT2 stage.Throughout the aging process,the interface between sphericalγ′phase andγmatrix exhibited a decreased composition fluctuation,while the interface fluctuation of coprecipitates was always significant.Thus,it can be inferred that the precipitation and evolution behaviors of secondary phases are controlled by the element diffusion at the interface.
作者
李亚微
谢光
柯于斌
卢玉章
黄亚奇
张健
LI Yawei;XIE Guang;KE Yubin;LU Yuzhang;HUANG Yaqi;ZHANG Jian(Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Spallation Neutron Source Science Center,Dongguan 523803,China;Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第8期1100-1108,共9页
Acta Metallurgica Sinica
基金
国家重点研发计划项目No.2021YFA1600603
国家自然科学基金项目Nos.52271042,51911530154,91860201,U2141206
国家科技重大专项项目No.J2019-VI-0010-0124
中国科学院依托重大科技基础设施的建制化科研项目No.JZHKYPT-2021-01
航空发动机及燃气轮机基础科学中心项目No.P2022-C-IV-001-001。
关键词
GH4169
热处理
小角中子散射
第二相
析出演化行为
GH4169
heat treatment
small-angle neutron scattering
second phase
precipitation and evolution behavior