title: Tensile property improvement of TWIP-cored three-layer steel sheets fabricated by hot-roll-bonding with low-carbon steel or interstitial-free steel.
abstract: TWIP-cored three-layer steel sheets were newly fabricated by hot rolling of TWIP steel sheet surrounded by low-carbon (LC) or interstitial-free (IF) steel sheets. TWIP/LC or TWIP/IF interfaces were well bonded without pores or voids, while a few pearlites were thinly formed along the interfaces. The strengths and elongation of the TWIP-cored sheets increased as the volume fraction of TWIP-cored region increased, and were also well matched with the ones calculated by a rule of mixtures based on volume fraction or force fraction. According to digital image correlation and electron back-scatter diffraction analyses, very high strain hardening effect in the initial deformation stage and active twin formation in the interfacial region beneficially affected the overall homogeneous deformation in the TWIP-cored sheets without any yield point phenomenon occurring in the LC sheet and serrations occurring in the TWIP sheet, respectively. These TWIP-cored sheets can cover a wide range of yield strength, tensile strength, and ductility levels, e.g., 320~498 MPa, 545~878 MPa, and 48~54%, respectively, by controlling the volume fraction of TWIP-cored region, and thus present new applications to multi-functional automotive steel sheets requiring excellent properties.
authors.affiliation: Center for Advanced Aerospace Materials Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Jaeyeong
authors.initials: J
authors.lastname: Park
authors.affiliation: Center for Advanced Aerospace Materials Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Jung-Su
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Center for Advanced Aerospace Materials Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Minju
authors.initials: M
authors.lastname: Kang
authors.affiliation: Center for Advanced Aerospace Materials Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Seok Su
authors.initials: SS
authors.lastname: Sohn
authors.affiliation: Steel Research Group Technical Research Laboratories, POSCO, Kwangyang, 545-090, Korea.
authors.forename: Won Tae
authors.initials: WT
authors.lastname: Cho
authors.affiliation: Center for Advanced Aerospace Materials Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Hyoung Seop
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Center for Advanced Aerospace Materials Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Sunghak
authors.initials: S
authors.lastname: Lee