TY - JOUR
T1 - Ultra-high strength and excellent ductility in multi-layer steel sheet of austenitic hadfield and martensitic hot-press-forming steels
AU - Park, Jaeyeong
AU - Jo, Min Cheol
AU - Song, Taejin
AU - Kim, Hyoung Seop
AU - Sohn, Seok Su
AU - Lee, Sunghak
N1 - Funding Information:
This work was supported by the Korea University Grant for the fifth author, and by Brain Korea 21 PLUS Project for Center for Creative Industrial Materials . H.S. Kim acknowledges the support by the National Research Foundation of Korea grant funded by the Korea government (MSIP) (No. 2014R1A2A1A10051322 ).
Publisher Copyright:
© 2019
PY - 2019/6/24
Y1 - 2019/6/24
N2 - An austenitic Hadfield steel sheet shows a relatively low yield strength of 0.4–0.5 GPa and serrated flows in spite of excellent tensile strength and ductility along with highly-sustained strain hardening. In order to overcome the shortcomings, a multi-layer steel (MLS) sheet was fabricated by a roll-bonding with an ultra-high-strength martensitic hot-press-forming (HPF) steel sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2% of C) to HPF (0.23% of C) layers, and could generate a kind of very thin multi-layers of 35 μm in thickness. All tensile properties of the Hadfield/HPF MLS sheet (yield strength; 946 MPa, tensile strength; 1291 MPa, elongation; 44.5%) were superior to those of the Hadfield sheet. Interestingly, the persistent elongation up to 44.5%, which is higher than that of the Hadfield steel, in the present MLS sheet is a quite unique and interesting characteristic. The simultaneous enhancement of strength and ductility of the MLS sheet was explained by the contributions of 1) populated twin formation, 2) generation of geometrically necessary dislocations (GNDs), and 3) increase of back stress inside thin interfacial layers.
AB - An austenitic Hadfield steel sheet shows a relatively low yield strength of 0.4–0.5 GPa and serrated flows in spite of excellent tensile strength and ductility along with highly-sustained strain hardening. In order to overcome the shortcomings, a multi-layer steel (MLS) sheet was fabricated by a roll-bonding with an ultra-high-strength martensitic hot-press-forming (HPF) steel sheet. Near the Hadfield/HPF interface, the carburized and decarburized layers were formed by the carbon diffusion from the Hadfield (1.2% of C) to HPF (0.23% of C) layers, and could generate a kind of very thin multi-layers of 35 μm in thickness. All tensile properties of the Hadfield/HPF MLS sheet (yield strength; 946 MPa, tensile strength; 1291 MPa, elongation; 44.5%) were superior to those of the Hadfield sheet. Interestingly, the persistent elongation up to 44.5%, which is higher than that of the Hadfield steel, in the present MLS sheet is a quite unique and interesting characteristic. The simultaneous enhancement of strength and ductility of the MLS sheet was explained by the contributions of 1) populated twin formation, 2) generation of geometrically necessary dislocations (GNDs), and 3) increase of back stress inside thin interfacial layers.
KW - Back stress
KW - Carbon diffusion
KW - Geometrically necessary dislocation
KW - Multi-layer steel (MLS) sheet
KW - Roll-bonding
UR - http://www.scopus.com/inward/record.url?scp=85065879701&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2019.05.046
DO - 10.1016/j.msea.2019.05.046
M3 - Article
AN - SCOPUS:85065879701
SN - 0921-5093
VL - 759
SP - 320
EP - 328
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
ER -