Relation between Intergranular Stress of Austenite and Martensitic Transformation in TRIP Steels Revealed by Neutron Diffraction

• Harjo Stefanus

  J-PARC Center, Japan Atomic Energy Agency

• Kawasaki Takuro

  J-PARC Center, Japan Atomic Energy Agency

• Tsuchida Noriyuki

  Graduate School of Engineering, University of Hyogo

• Morooka Satoshi

  J-PARC Center, Japan Atomic Energy Agency Materials Sciences Research Center, Japan Atomic Energy Agency

• Gong Wu

  J-PARC Center, Japan Atomic Energy Agency Elements Strategy Initiative for Structural Materials, Kyoto University

Abstract

In situ neutron diffraction measurements of two low-alloy steels and a 304-type stainless steel during tensile and creep tests were performed at room temperature. Changes in the diffraction pattern, the integrated peak intensities of austenite (γ), and the peak positions of γ were analyzed and discussed to elucidate the relationship between intergranular stress in γ and the occurrence of martensitic transformation during deformation. Tensile loading experiments revealed that the susceptibility to martensitic transformation depended on the γ-(hkl) grains, where γ-(111) grains underwent martensitic transformation at the latest. The volume fractions of γ were found to decrease under an applied load but to remain almost unchanged under constant load in creep tests, where the lattice strains of γ-(hkl) grains were mostly unchanged. The γ-hkl dependence of the susceptibility to martensitic transformation was found to be controlled by the shear stress levels in γ-(hkl) grains, which were affected by the intergranular stress partitioning during deformation.

Journal

• ISIJ International

  ISIJ International 61 (2), 648-656, 2021-02-15

  The Iron and Steel Institute of Japan

Keywords

• martensitic transformation
• TRIP
• tension
• creep
• neutron diffraction

Details

• CRID: 1390850092191615744
• NII Article ID: 130007987394
• DOI: 10.2355/isijinternational.isijint-2020-503
• ISSN: 13475460
• ISSN: 09151559
• Web Site: https://www.jstage.jst.go.jp/article/isijinternational/61/2/61_ISIJINT-2020-503/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed