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Formation Mechanism of Laves Phase with Two Morphologies in a Novel 9Cr-3W-3Co-1CuVNbB Steel During Creep Process

37 Pages Posted: 21 May 2021 Publication Status: Under Review

See all articles by Bo Xiao

Bo Xiao

Tianjin University - School of Materials Science and Engineering; Tianjin University - Tianjin Key Laboratory of Advanced Joining Technology

Haokai Dong

Tsinghua University - Key Laboratory for Advanced Materials of Ministry of Education

Tao Yang

City University of Hong Kong (CityUHK) - Department of Materials Science and Engineering

Cyril Cayron

Ecole Polytechnique Fédérale de Lausanne - Laboratory of ThermoMechanical Metallurgy (LMTM)

Shenbao Jin

Nanjing University of Science and Technology - School of Material Science and Engineering

Boxuan Cao

City University of Hong Kong

Yongdian Han

Tianjin University - School of Materials Science and Engineering

Lei Zhao

Tianjin University - School of Materials Science and Engineering

Gang Sha

Nanjing University of Science and Technology - School of Material Science and Engineering

Ji-jung Kai

City University of Hong Kong (CityUHK) - Centre for Advanced Nuclear Safety and Sustainable Development; City University of Hong Kong (CityUHK) - Department of Mechanical and Biomedical Engineering

Roland Logé

Ecole Polytechnique Fédérale de Lausanne - Laboratory of ThermoMechanical Metallurgy (LMTM)

Lianyong Xu

Tianjin University - School of Materials Science and Engineering; Harbin Institute of Technology - State Key Laboratory of Advanced Welding and Joining; Tianjin University - Tianjin Key Laboratory of Advanced Joining Technology

Abstract

Coarse Laves precipitates can strongly deteriorate the creep rupture strength of tempered martensite ferritic heat-resistant steels. In this study, we demonstrated two independent paths, i.e., isolated at the interface and neighboring phase-assisted, of Laves phase precipitation during the creep process in G115 steel. In particular, blocky-like Laves phase particles adjacent to the M23C6 and Cu-rich precipitate (CRP) are firstly captured. Most of the Laves phases are found to precipitate at the high-angle grain boundaries (HAGBs) whereas only a small amount precipitate at the low-angle grain boundaries (LAGBs). Among them, the M 23 C 6 are more preferential nucleation sites for the Laves phase. Crystallographic analysis indicates that the Laves phase obeys a specific orientation relationship (OR) with the M23C6, i.e., (110)M23C6// (10‾13)Laves and [1‾13] M23C6 // [ 03‾31 ]Laves. Solute segregation at grain boundaries and interphase boundaries (M23C6/ferrite and CRP/ferrite) is expected to be the main cause for the heterogeneous precipitation of Laves phase. The growth of the isolated Laves phase is dominated by the grain boundary diffusion mechanism, while that of Laves phase next to theM23C6 and CRP is controlled by the trans-interface diffusion controlled (TIDC) mechanism, which results in two morphologies of Laves phase. The work may improve the understanding of roles of M23C6 and CRP in precipitation mechanism of Laves phase, and provide a more accurate guide for the development of heat-resistant steels with superior creep strength.

Keywords: G115 steel; Laves phase; M23C6, orientation relationship (OR), heterogeneous precipitation

Suggested Citation

Xiao, Bo and Dong, Haokai and Yang, Tao and Cayron, Cyril and Jin, Shenbao and Cao, Boxuan and Han, Yongdian and Zhao, Lei and Sha, Gang and Kai, Ji-jung and Logé, Roland and Xu, Lianyong, Formation Mechanism of Laves Phase with Two Morphologies in a Novel 9Cr-3W-3Co-1CuVNbB Steel During Creep Process. Available at SSRN: https://ssrn.com/abstract=3850522 or http://dx.doi.org/10.2139/ssrn.3850522

Bo Xiao

Tianjin University - School of Materials Science and Engineering

Tianjin
China

Tianjin University - Tianjin Key Laboratory of Advanced Joining Technology

Tianjin, 300350
China

Haokai Dong

Tsinghua University - Key Laboratory for Advanced Materials of Ministry of Education ( email )

China

Tao Yang

City University of Hong Kong (CityUHK) - Department of Materials Science and Engineering

83 Tat Chee Avenue
Kowloon
Hong Kong

Cyril Cayron

Ecole Polytechnique Fédérale de Lausanne - Laboratory of ThermoMechanical Metallurgy (LMTM)

Rue de la Maladière 71b
Neuchâtel, 2000
Switzerland

Shenbao Jin

Nanjing University of Science and Technology - School of Material Science and Engineering

No.219, Ningliu Road
Nanjing, Jiangsu
China

Boxuan Cao

City University of Hong Kong

Centre for Applied One Health Research and Policy
Hong Kong

Yongdian Han

Tianjin University - School of Materials Science and Engineering ( email )

Tianjin
China

Lei Zhao

Tianjin University - School of Materials Science and Engineering

Tianjin
China

Gang Sha

Nanjing University of Science and Technology - School of Material Science and Engineering

No.219, Ningliu Road
Nanjing, Jiangsu
China

Ji-jung Kai

City University of Hong Kong (CityUHK) - Centre for Advanced Nuclear Safety and Sustainable Development ( email )

83 Tat Chee Avenue
Kowloon
Hong Kong

City University of Hong Kong (CityUHK) - Department of Mechanical and Biomedical Engineering ( email )

83 Tat Chee Avenue
Kowloon
Hong Kong

Roland Logé

Ecole Polytechnique Fédérale de Lausanne - Laboratory of ThermoMechanical Metallurgy (LMTM)

Rue de la Maladière 71b
Neuchâtel, 2000
Switzerland

Lianyong Xu (Contact Author)

Tianjin University - School of Materials Science and Engineering ( email )

Tianjin
China

Harbin Institute of Technology - State Key Laboratory of Advanced Welding and Joining ( email )

92 West Dazhi Street
Nan Gang District
Harbin, 150001
China

Tianjin University - Tianjin Key Laboratory of Advanced Joining Technology ( email )

Tianjin, 300350
China

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