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Solute-Dislocation Interactions and Creep-Enhanced Cu Precipitation in a Novel Ferritic-Martensitic Steel

36 Pages Posted: 6 Mar 2020 Publication Status: Accepted

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

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

Cyril Cayron

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

Jing Xue

Nanjing University of Science and Technology - Herbert Gleiter Institute of Nanoscience

Gang Sha

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

Roland Logé

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

Abstract

G115 steel has gained a growing interesting recently for its use in next-generation ultra-supercritical power plant applications. Due to the high densities of dislocations and lath martensite boundaries in G115 steel, interactions between solutes and dislocations result in unique microstructural evolution during creep with the formation of dense Cu-rich precipitates (CRPs) and M23C6 carbides. Atom-probe tomography reveals that Mn is preferentially associated with CRPs, probably because the Mn atoms reduce the critical energy of nucleation. Solute-dragging and precipitate-pinning effects enhance the formation of dislocation network during earlier creep deformation. Compared with aged G115 steel, long-term creep deformation accelerates the coarsening of CRPs. The fast diffusion of solutes along dislocations, dislocation network walls, and lath boundaries significantly increases the CRP coarsening kinetics. Particle coarsening reduces the pinning strength, causing the dislocation density to decrease and the dislocation network to disappear during long creep stages. Our results enhance our understanding of CRP evolution in G115 steel during creep and provide a guide for the design of novel heat-resistant steels with excellent creep strength.

Keywords: G115 steel, creep, precipitation, three-dimensional atom probe, coarsening mechanism

Suggested Citation

Xiao, Bo and Xu, Lianyong and Cayron, Cyril and Xue, Jing and Sha, Gang and Logé, Roland, Solute-Dislocation Interactions and Creep-Enhanced Cu Precipitation in a Novel Ferritic-Martensitic Steel. Available at SSRN: https://ssrn.com/abstract=3549010 or http://dx.doi.org/10.2139/ssrn.3549010

Bo Xiao

Tianjin University - School of Materials Science and Engineering

Tianjin
China

Tianjin University - Tianjin Key Laboratory of Advanced Joining Technology

Tianjin, 300350
China

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

Cyril Cayron

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

Rue de la Maladière 71b
Neuchâtel, 2000
Switzerland

Jing Xue

Nanjing University of Science and Technology - Herbert Gleiter Institute of Nanoscience

No.219, Ningliu Road
Nanjing, Jiangsu
China

Gang Sha

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

No.219, Ningliu Road
Nanjing, Jiangsu
China

Roland Logé

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

Rue de la Maladière 71b
Neuchâtel, 2000
Switzerland

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