| Fusion boundary evolution,precipitation behaviour,and interaction with dislocations in an Fe–22Cr–15Ni steel weldment during long-term creep |
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| 摘 要： | A tungsten inert gas welded joint between a novel heat-resistant austenitic steel and ERNiCrCoMo-1 weld metal was investigated before and after creep in this study. The evolution of the microstructures in the base and weld metals was discussed based on the electron back-scatter diffraction(EBSD) and transmission electron microscopy(TEM) analyses. The preferred orientations of the fusion boundary after creep revealed the influence of the applied stress on creep deformation mechanism. A cooperative nucleation process of M_(23)C_6 carbides in the base metal was proposed. The finely distributed Cu-rich phase was cut off by the dislocations during creep, leading to increased mean size and reduced amount of the nano-Cu phase. A modified triple-precipitate hardening model was constructed based on TEM observations of the interactions between the particles and the dislocations in the base metal after creep at 200 MPa. The evolution of a μ phase in the weld metal involved epitaxial growth and dissolving into the matrix.
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| 收稿时间： | 24 September 2018 |
Fusion boundary evolution,precipitation behaviour,and interaction with dislocations in an Fe–22Cr–15Ni steel weldment during long-term creep |
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| Institution: | 1. School of Materials Science and Engineering, Tianjin University, Tianjin 300350, China;2. Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350, China;3. State Key Laboratory of Engines, Tianjin University, Tianjin 300350, China;4. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China |
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| Abstract: | A tungsten inert gas welded joint between a novel heat-resistant austenitic steel and ERNiCrCoMo-1 weld metal was investigated before and after creep in this study. The evolution of the microstructures in the base and weld metals was discussed based on the electron back-scatter diffraction (EBSD) and transmission electron microscopy (TEM) analyses. The preferred orientations of the fusion boundary after creep revealed the influence of the applied stress on creep deformation mechanism. A cooperative nucleation process of M23C6 carbides in the base metal was proposed. The finely distributed Cu-rich phase was cut off by the dislocations during creep, leading to increased mean size and reduced amount of the nano-Cu phase. A modified triple-precipitate hardening model was constructed based on TEM observations of the interactions between the particles and the dislocations in the base metal after creep at 200 MPa. The evolution of a μ phase in the weld metal involved epitaxial growth and dissolving into the matrix. |
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| Keywords: | Heat-resistant steel weldment Creep EBSD Nucleation mechanism Nano Cu-rich phase |
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