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Title: Microstructural evolution of delta ferrite in SAVE12 steel under heat treatment and short-term creep

Abstract

This research focused on the formation and microstructural evolution of delta ferrite phase in SAVE12 steel. The formation of delta ferrite was due to the high content of ferrite forming alloy elements such as Cr, W, and Ta. This was interpreted through either JMatPro-4.1 computer program or Cr{sub eq} calculations. Delta ferrite was found in bamboo-like shape and contained large amount of MX phase. It was surrounded by Laves phases before creep or aging treatment. Annealing treatments were performed under temperatures from 1050 Degree-Sign C to 1100 Degree-Sign C and various time periods to study its dissolution kinetics. The result showed that most of the delta ferrite can be dissolved by annealing in single phase austenitic region. Dissolution process of delta ferrite may largely depend on dissolution kinetic factors, rather than on thermodynamic factors. Precipitation behavior during short-term (1100 h) creep was investigated at temperature of 600 Degree-Sign C under a stress of 180 MPa. The results demonstrated that delta ferrite became preferential nucleation sites for Laves phase at the early stage of creep. Laves phase on the boundary around delta ferrite showed relatively slower growth and coarsening rate than that inside delta ferrite. - Highlights: Black-Right-Pointing-Pointer Delta ferrite ismore » systematically studied under heat treatment and short-term creep. Black-Right-Pointing-Pointer Delta ferrite contains large number of MX phase and is surrounded by Laves phases before creep or aging treatment. Black-Right-Pointing-Pointer Formation of delta ferrite is interpreted by theoretical and empirical methods. Black-Right-Pointing-Pointer Most of the delta ferrite is dissolved by annealing in single phase austenitic region. Black-Right-Pointing-Pointer Delta ferrite becomes preferential nucleation sites for Laves phase at the early stage of creep.« less

Authors:
 [1]; ; ;  [1];  [2];  [1]
  1. School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)
  2. School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)
Publication Date:
OSTI Identifier:
22163154
Resource Type:
Journal Article
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 73; Journal Issue: Complete; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-5803
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; AUSTENITIC STEELS; CREEP; DISSOLUTION; FERRITE; FERRITES; KINETICS; LAVES PHASES; MICROSTRUCTURE; NUCLEATION; PRECIPITATION

Citation Formats

Li, Shengzhi, E-mail: lishengzhi@sjtu.edu.cn, Eliniyaz, Zumrat, Zhang, Lanting, Sun, Feng, Shen, Yinzhong, and Shan, Aidang, E-mail: adshan@sjtu.edu.cn. Microstructural evolution of delta ferrite in SAVE12 steel under heat treatment and short-term creep. United States: N. p., 2012. Web. doi:10.1016/J.MATCHAR.2012.08.009.
Li, Shengzhi, E-mail: lishengzhi@sjtu.edu.cn, Eliniyaz, Zumrat, Zhang, Lanting, Sun, Feng, Shen, Yinzhong, & Shan, Aidang, E-mail: adshan@sjtu.edu.cn. Microstructural evolution of delta ferrite in SAVE12 steel under heat treatment and short-term creep. United States. doi:10.1016/J.MATCHAR.2012.08.009.
Li, Shengzhi, E-mail: lishengzhi@sjtu.edu.cn, Eliniyaz, Zumrat, Zhang, Lanting, Sun, Feng, Shen, Yinzhong, and Shan, Aidang, E-mail: adshan@sjtu.edu.cn. Thu . "Microstructural evolution of delta ferrite in SAVE12 steel under heat treatment and short-term creep". United States. doi:10.1016/J.MATCHAR.2012.08.009.
@article{osti_22163154,
title = {Microstructural evolution of delta ferrite in SAVE12 steel under heat treatment and short-term creep},
author = {Li, Shengzhi, E-mail: lishengzhi@sjtu.edu.cn and Eliniyaz, Zumrat and Zhang, Lanting and Sun, Feng and Shen, Yinzhong and Shan, Aidang, E-mail: adshan@sjtu.edu.cn},
abstractNote = {This research focused on the formation and microstructural evolution of delta ferrite phase in SAVE12 steel. The formation of delta ferrite was due to the high content of ferrite forming alloy elements such as Cr, W, and Ta. This was interpreted through either JMatPro-4.1 computer program or Cr{sub eq} calculations. Delta ferrite was found in bamboo-like shape and contained large amount of MX phase. It was surrounded by Laves phases before creep or aging treatment. Annealing treatments were performed under temperatures from 1050 Degree-Sign C to 1100 Degree-Sign C and various time periods to study its dissolution kinetics. The result showed that most of the delta ferrite can be dissolved by annealing in single phase austenitic region. Dissolution process of delta ferrite may largely depend on dissolution kinetic factors, rather than on thermodynamic factors. Precipitation behavior during short-term (1100 h) creep was investigated at temperature of 600 Degree-Sign C under a stress of 180 MPa. The results demonstrated that delta ferrite became preferential nucleation sites for Laves phase at the early stage of creep. Laves phase on the boundary around delta ferrite showed relatively slower growth and coarsening rate than that inside delta ferrite. - Highlights: Black-Right-Pointing-Pointer Delta ferrite is systematically studied under heat treatment and short-term creep. Black-Right-Pointing-Pointer Delta ferrite contains large number of MX phase and is surrounded by Laves phases before creep or aging treatment. Black-Right-Pointing-Pointer Formation of delta ferrite is interpreted by theoretical and empirical methods. Black-Right-Pointing-Pointer Most of the delta ferrite is dissolved by annealing in single phase austenitic region. Black-Right-Pointing-Pointer Delta ferrite becomes preferential nucleation sites for Laves phase at the early stage of creep.},
doi = {10.1016/J.MATCHAR.2012.08.009},
journal = {Materials Characterization},
issn = {1044-5803},
number = Complete,
volume = 73,
place = {United States},
year = {2012},
month = {11}
}