EBSD parameter assessment and constitutive models of crept HR3C austenitic steel  

作　　者：Jie Zhang Zheng-fei Hu Zhen Zhang 

机构地区：[1]Shanghai Key Laboratory for R&D and Application of Metallic Functional Materials,School of Materials Science and Engineering,Tongji University,Shanghai 201804,China [2]School of Materials Science and Engineering,Nanjing Institute of Technology,Nanjing 211167,Jiangsu,China

出　　处：《Journal of Iron and Steel Research International》2023年第4期772-781,共10页

基　　金：the National Natural Science Foundation of China(Grant number 51971163);Tongji University Test Fund(Grant number 2022GX060).

摘　　要：Creep damage and evolution of HR3C steel at 650℃ were investigated using electron backscatter diffraction(EBSD),and EBSD-based parameter assessments were conducted.EBSD analyses show that the grain size is almost unchanged and no obvious texture formed after creep at different creep rates.The lowest proportion of low Σ coincidence site lattice grain boundaries under 150 MPa implies that the primary twin structures are preserved under the low stress level,while some twin structures evolved into general grain boundaries at the high creep level.Two main damage features of microcracks and cavities can be seen along the grain boundaries:the former emerged at higher stress levels,while the latter appeared at the lower stress level,and both were shown under medium stress.Band contrast shows that the most severe creep damage is present at 170 MPa.It implies that the creep mechanism differs distinctly under different stress levels,and the transition point is around 170 MPa.Kernel average misorientation is better to describe the local plastic deformation related to the strain distribution while grain reference orientation deviation describes the inhomogeneous strain distribution.Creep lifetime prediction models including the isothermal method,Larson-Miller parameter method and Monkman–Grant relation were evaluated by the experimental data and literature data,and they are valid for predicting creep behavior.

关 键 词：Austenitic heat-resistant steel Creep damage Electron backscatter diffraction Creep constitutive model Creep lifetime prediction 

分 类 号：X70[环境科学与工程—环境工程]