Microstructural evolution and mechanical properties of a new Ni-based heat-resistant alloy during aging at 750℃

作     者：Zhong-liang Tian Sen-bao Jiang Zheng-zong Chen Han-sheng Bao Zheng-dong Liu 

作者机构：Institute for Special SteelsCentral Iron and Steel Research Institute College of Material Science & EngineeringTaiyuan Science & Technology University 

出 版 物：《Journal of Iron and Steel Research International》 (J. Iron Steel Res. Int.)

年 卷 期：2017年第24卷第5期

页      面：513-519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）] 

基　　金：supported by National Key Research and Development Plan(2016YFB0300203) National Energy Application Technology Research and Engineering Demonstration Project(NY20150101) 

主　　题：Aging Precipitation Microstruetural evolution Mechanical property Heat-resistant alloy 

摘      要：Microstructural evolution and mechanical properties of a new candidate Ni-based heat-resistant alloy for advanced ultra-supercritical （A-USC） steam turbine rotors were investigated during aging at 750℃ up to 10000 h. The evolutions of γ＇ particles inside austenitic grain and M_23 C_6 carbides along grain boundaries were characterized according to their morphologies, distributions, and growth kinetics. Mean radius of the γ＇ spherical particles grew from 20.3 to 90.0 nm after aging for 10000 h, and;the corresponding coarse- ning behavior was conformed to the law of Lifschitz-Slyosovd-Wagner （LSW）. The weight fraction of γ＇ particles slightly increased from 10.0 to 12.0 wt. % after aging of long duration at 750 ℃.The Cr-rich M_23C_6 carbides discontinuously precipitated along grain boundaries, while other detrimental phases were not formed during the aging treatment, and hence the strength of grain boundary was enhanced by these discontinuously distributed carbides. The critical size of γ＇ had a direct influence on the maximum hardness of this alloy. Moreover, this alloy presented a good impact toughness for the safety after long time aging at high temperature.