Nanoindentation behavior and creep-induced cracking of long-term crept austenitic steel at 650℃  

作　　者：Zhen Zhang Yu-hang Duan Shuai Wang Jin-shan Chen An-zhe Wang Xiang-yang Mao Yuan-ji Shi Jie Zhang Ming Liu Zheng-fei Hu 

机构地区：[1]School of Materials Science and Engineering,Nanjing Institute of Technology,Nanjing,211167,Jiangsu,China [2]Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology,Nanjing,211167,Jiangsu,China [3]Jiangsu Wind Power Engineering Technology Center,Nanjing,210023,Jiangsu,China [4]Nanjing Vocational University of Industry Technology,Nanjing,210023,Jiangsu,China [5]Baoshan Iron&Steel Co.,Ltd.,Shanghai,201900,China [6]Fujian Provincial Key Laboratory of Terahertz Functional Devices and Intelligent Sensing,School of Mechanical Engineering and Automation,Fuzhou University,Fuzhou,350116,Fujian,China [7]School of Materials Science and Engineering,Tongji University,Shanghai,201804,China

出　　处：《Journal of Iron and Steel Research International》2024年第2期464-474,共11页

基　　金：grateful for the financial support from the National Natural Science Foundation of China(51904156,51971163 and 51705082);the Open Fund of Jiangsu Wind Power Engineering Technology Center(ZK22-03-02);the Ten thousand talents project of Zhejiang Province(2019R52056).

摘　　要：The grain boundary(GB)damage of long-term crept HR3C(25Cr–20Ni–Nb–N)austenitic steel with solid solution state was investigated by nanoindentation test accompanied with in-situ electron back-scattered diffraction.The corresponding microstructure was characterized by scanning electron microscopy and transmission electron microscopy.Results show that the increase in nanoindentation hardness at the GBs and triple grain junctions may be related to the dislocation accumulation and carbide growth during the creep.Coarsened M23C6 and dislocations piling-up at the GB accelerate the nucleation and coalescence of creep cavity along the GB.The nanoindentation hardness in grains varies with orientation of the stress axis.The orientation difference of neighbor grains may induce local high geometrically necessary dislocation densities and strain gradients near the GB,consequently causing stress concentration and subsequent crack growth at specific GBs.

关 键 词：Austenitic steel CREEP NANOINDENTATION Grain orientation Creep-induced cracking 

分 类 号：TG142[一般工业技术—材料科学与工程]