摘要
研究了W-4Re-0.27HfC(wt%)合金在1800、1900、2000℃下的蠕变性能,结合扫描电子显微镜(SEM)、背向散射电子衍射(EBSD)、第一性原理计算(DFT)等方法,分析了蠕变后W-4Re-0.27HfC合金的晶粒尺寸、晶粒类型、位错密度、断口形貌等,讨论了W-4Re-0.27HfC合金蠕变失效的机制。结果表明,蠕变温度为1800、1900、2000℃时,稳态蠕变速率分别为9.8×10^(-6)、1.0×10^(-5)、2.1×10^(-5)s^(-1)。随着蠕变温度的升高,小角度晶界占比下降而大角度晶界占比增高,平均晶粒尺寸增加。蠕变过程中晶粒发生塑性变形,大角度晶界在塑性变形阶段变形相容性差,促进形成孔洞,加速蠕变失效。蠕变过程中第二相粒子HfC氧化严重,DFT计算结果表明HfC氧化后与基体间的界面结合能将从–11.221 J/m^(2)降低至–3.935 J/m^(2),降低第二相的强化作用。
The creep properties of W-4Re-0.27HfC(wt%)alloy at temperatures of 1800,1900,and 2000℃was investigated by SEM,EBSD,and density functional theory(DFT).The grain size,grain type,dislocation density,fracture morphology,and the mechanism of creep failure of W-4Re-0.27HfC alloy ware analyzed after creep at different temperatures.The results indicate that the steady-state creep rates at creep temperatures of 1800,1900 and 2000°C are 9.8×10^(-6),1.0×10^(-5),and 2.1×10^(-5)s^(-1),respectively.With the increase in creep temperature,the proportion of low-angle grain boundaries decreases while the proportion of high-angle grain boundaries increases,resulting in the increase in average grain size.During the creep process,grain undergoes plastic deformation,forming numerous ductile dimples.The poor deformation compatibility of high-angle grain boundaries leads to the formation of voids,accelerating creep failure.EDS results illustrate that the HfC particles in W-4Re-0.27HfC alloy are oxidized severely.DFT calculations show that the interface binding energy between HfC and matrix decreases from–11.221 J/m^(2)to–3.935 J/m^(2)after HfC oxidation,reducing the strengthening effect of the second phase.
作者
郑铮辉
赖陈
董丽然
董帝
熊宁
王滢
苗国威
张迎晓
王金淑
Zheng Zhenghui;Lai Chen;Dong Liran;Dong Di;Xiong Ning;Wang Ying;Miao Guowei;Zhang Yingxiao;Wang Jinshu(School of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China;ATTL Advanced Materials Co.,Ltd,Beijing 100094,China)
出处
《稀有金属材料与工程》
北大核心
2025年第9期2319-2324,共6页
Rare Metal Materials and Engineering
基金
国家重点研发计划(2022YFB3705402)。
关键词
钨铼合金
蠕变性能
蠕变失效
第二相粒子
W-Re alloy
creep property
creep failure
second-phase particle
作者简介
郑铮辉,男,1997年生,博士生,北京工业大学材料科学与工程学院,北京100124,电话:010-67391101,E-mail:zhengzhenghui@emails.bjut.edu.cn;Corresponding author:Wang Jinshu,Ph.D.,Professor,School of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,P.R.China,E-mail:wangjsh@bjut.edu.cn。
