On the microstructural evolution in 12% Cr turbine steel during low cycle fatigue at elevated temperature

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:773

Article

Rae, Y.¹  Guo, X.¹  Benaarbia, A.²  Neate, N.¹  Sun, W.¹ 

[1] Univ Nottingham, Dept Mech Mat & Mfg Engn, Nottingham NG7 2RD, Notts, England

[2] Univ Lorraine, LEM3, CNRS, Arts & Metiers ParisTech, F-57000 Metz, France

关键词: Low cycle fatigue;    Cyclic softening;    Sub-grain coarsening;    Annihilation of dislocations;    Martensite reorientation;   

DOI  :  10.1016/j.msea.2019.138864

来源: Elsevier

【 摘 要 】

In order to better understand the physical process of deformation and cyclic softening a 12% Cr martensitic stainless steel FV566 has been cyclically tested at high temperature in strain control. Increase in temperature was found to increase the cyclic life, softening rate and viscous stress magnitude. An increase in the dwell time led to the acceleration of the material degradation. The microstructure changes and dominating deformation mechanisms were investigated by means of scanning electron microscopy, electron backscatter diffraction and transmission electron microscopy. The results have revealed a gradual sub-grain coarsening, transformation of lath structure into fine equiaxed subgrains, and misorientation angle development in blocks and packets until material failure. The softening behaviour was attributed to the mutual annihilation of the dislocations and rearrangement of the residual dislocation in the low energy structures.

【 授权许可】

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