摘要
为探究双级时效工艺对铸造镍基多晶高温合金K417G微观组织和性能的影响,通过扫描电镜、万能试验机等仪器,研究了单级时效和双级时效后高温合金K417G中γ′相形貌、碳化物及950℃拉伸性能,并对拉伸断口进行分析,研究其断裂机理。结果表明,单级时效后,枝晶干处γ′相呈类球形分布,体积分数为54.63%,抗拉强度为481.25 MPa。碳化物主要为MC型碳化物,晶界处有点状M_(23)C_(6)型碳化物析出。双级时效后,枝晶干处γ′相呈立方状分布,体积分数略升高至56.54%。碳化物类型及分布情况与单级时效处理后变化不大。与单级时效相比,双级时效后抗拉强度提升了13.97%。对断口分析后发现,单级时效处理后合金断裂方式为韧性断裂,双级时效处理后,为脆性和韧性断裂混合型。两种工艺下裂纹萌生的起点和扩展通道主要为碳化物与基体界面分离。双级时效后立方状γ′相能更有效阻碍位错运动,提升合金的抗拉强度。
To investigate the effect of double aging treatment on the microstructure and properties of cast nickel based polycrystalline superalloy K417G,the morphology ofγ′phase,carbides,and tensile properties at 950℃after single and double aging were studied using instruments such as scanning electron microscopy and universal testing machine.Additionally,the fracture mechanism was analyzed by examining the tensile fracture surface.The results indicate that after single aging,the tensile strength is 481.25 MPa,theγ′phase at the dendritic grain boundaries exhibits a nearly spherical distribution with a volume fraction of 54.63%,and blocky MC carbides exist both at grain boundaries and within grains,while point-like M_(23)C_(6) carbides distribute along grain boundaries.After double aging,theγ′phase at dendritic grain boundaries exhibits a cubic distribution,with a slight increase in volume fraction to 56.54%.The carbides appear as blocky MC and point-like M_(23)C_(6),with the distribution patterns consistent with those after single aging.Compared to that after single aging,the tensile strength increases by 13.97%after double aging.The fracture analysis reveals that after single aging,the alloy exhibits ductile fracture,while after double aging,it demonstrates a mixed mode of brittle and ductile fracture.In both processes,the carbides play a crucial role as initiation points and propagation paths for cracks by debonding from the matrix.The cubicγ′phase after double aging can more effectively impedes dislocation motion,thereby enhancing the tensile strength of the alloy.
作者
曹后帆
玄伟东
樊志明
段磊鑫
鲍俊
王保军
屠挺生
任忠鸣
Cao Houfan;Xuan Weidong;Fan Zhiming;Duan Leixin;Bao Jun;Wang Baojun;Tu Tingsheng;Ren Zhongming(State Key Laboratory of Advanced Special Steel,Shanghai University,Shanghai 200444,China;AECC Commercial Aircraft Engine Co.,Ltd.,Shanghai 200241,China)
出处
《金属热处理》
北大核心
2025年第6期170-176,共7页
Heat Treatment of Metals
基金
国家自然科学基金(52274386,92060104)
上海市经信委工业强基项目(GYQJ-2022-2-02)
航空科学基金重点项目(2022Z0470S6001)
上海市商用飞机发动机联合创新项目(AR966)。
关键词
高温合金
热处理
γ′相
拉伸性能
superalloy
heat treatment
γ′phase
tensile properties
作者简介
曹后帆(1998-),男,硕士研究生,主要研究方向为高温合金的组织和性能,E-mail:caohoufan1@163.com;通信作者:玄伟东,教授,E-mail:wdxuan@shu.edu.cn。
