【作者】 郑磊； 张麦仓； 董建新； 胡尧和；

【Author】 Zheng Lei Zhang Maicang Dong Jianxin Hu Yaohe (School of Materials Science and Engineering,USTB,Beijing 100083,China)

【机构】 北京科技大学材料科学与工程学院；

【摘要】 本文建立了 GH3690合金在特殊时效处理（TT 处理）过程中晶界碳化物的长大及贫铬区演化模型,并首次利用 DICTRA 软件及相应数据库,分析了 TT 处理对晶界附近铬元素扩散和晶界碳化物长大机制的影响。同时,实验观察了晶界贫铬区和碳化物状况,验证了动力学计算结果的可靠性,证实了 TT 处理温度和时间是影响晶界碳化物长大和贫铬区演化的主要因素。另外,对中外 GH3690合金管材进行了全面对比分析,对管材在高纯水模拟运行后的组织变化规律进行了研究,发现模拟运行后基体组织变化不大,表面生成微米数量级厚度的氧化膜,其组分为六方结构的（Fe,Cr）₂O₃。更多还原

【Abstract】 In present paper,the model about the growth of grain boundary carbides and chromium depletion region during ther- mal treatment（TT）for GH3690 alloy is founded.Using DICTRA software and its corresponding databases,the effects of Tr on both Cr diffusion and carbides growth at grain boundaries are analyzed for the first time.At the same time,Cr depletion and ear- bides growth are observed experimentally,which validates the reliability of the calculated results obtained by DICTRA and con- f’u’ms that the temperature and time of TT are key factors affecting the growth of carbides and depletion of Cr at grain boundaries.Moreover,four kinds of GH3690 alloy tubes after simulated service under high temperature pure water environment are studied.The results show that the matrix structures of all alloys are stable and the oxidation films,such as（Fe,Cr）₂O₃, are formed in the thickness of several microns.更多还原