Strategy of complex carbides in microalloyed 4Mn steels processed by quenching and austenite reversion

Shao-Lun Lu; Shan-Chun Yang; Kangying Zhu; Yi-Sheng Chen; Julie M. Cairney; Chun-Ming Lin; Hung-Wei Yen

Materials & Design (Jun 2023)

Strategy of complex carbides in microalloyed 4Mn steels processed by quenching and austenite reversion

Shao-Lun Lu,
Shan-Chun Yang,
Kangying Zhu,
Yi-Sheng Chen,
Julie M. Cairney,
Chun-Ming Lin,
Hung-Wei Yen

Affiliations

Shao-Lun Lu: Department of Materials Science and Engineering, National Taiwan University, 10617 Taipei, Taiwan
Shan-Chun Yang: Department of Materials Science and Engineering, National Taiwan University, 10617 Taipei, Taiwan
Kangying Zhu: ArcelorMittal Research SA, Voie Romaine, 57280 Maizieres les Metz, France
Yi-Sheng Chen: Department of Materials Science and Engineering, National Taiwan University, 10617 Taipei, Taiwan; Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006, Australia; School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia
Julie M. Cairney: Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006, Australia; School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia
Chun-Ming Lin: Department of Mechanical Engineering, Minghsin University of Science and Technology, 30401 Hsinchu, Taiwan
Hung-Wei Yen: Department of Materials Science and Engineering, National Taiwan University, 10617 Taipei, Taiwan; Corresponding Author.

Journal volume & issue: Vol. 230
p. 111951

Abstract

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This work describes a strategy to employ complex carbides for high-yield microalloyed 4Mn steels processed by quenching and reversion (Q&R). The nano/microstructural details are investigated by using electron microscopy and atom probe. It is found that complex carbides are classified into two types and contribute to yield strength in different ways. First, coarse carbides (MC1), which are retained after austenization and quenching, provide the Zener pinning effect and contribute to strengthening by microstructure refinement and precipitation hardening. Second, nanoscale carbides (MC2), which precipitate in martensite during austenite reversion, provide precipitation hardening. Furthermore, the precipitation of MC1 accelerates austenite reversion due to the finer martensite microstructure. Hence, the strengthening effects and TRIP effect can be tuned by controlling the proportion of the two types of carbide. This concept is validated in Ti-Mo 4Mn steel, which exhibits a high yield strength of about 850 MPa, a high ultimate tensile strength of about 950 MPa, and excellent elongation of over 20%. The complex carbide strategy is able to increase yield strength without sacrificing much ductility for Q&R medium-Mn steels.

Published in Materials & Design

ISSN: 0264-1275 (Print); 1873-4197 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.journals.elsevier.com/materials-and-design

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