TY - JOUR
T1 - Dynamic torsional deformation behavior of ultra-fine-grained dual-phase steel fabricated by equal channel angular pressing
AU - Hwang, Byoungchul
AU - Kim, Yang Gon
AU - Lee, Sunghak
AU - Hwang, Duck Young
AU - Shin, Dong Hyuk
PY - 2007/12
Y1 - 2007/12
N2 - Dynamic torsional deformation behavior of an ultra-fine-grained dual-phase steel fabricated by equal channel angular pressing (ECAP) was investigated and compared with that of an equal channel angular pressed (ECAPed) ultra-fine-grained low-carbon steel. Tensile and dynamic torsional tests were conducted on these two steels, and the deformed microstructures were observed to investigate the dynamic deformation behavior. The ECAPed low-carbon steel consisted of very fine, elongated ferrite-pearlite grains of 0.5 μm in size, and the ECAPed dual-phase steel consisted of ferrite-martensite grains of 1 μm in size. The dynamic torsional test results indicated that maximum shear stress of the dual-phase steel was lower than that of the conventional steel, but that fracture shear strain was higher in the dual-phase steel. Some adiabatic shear bands were observed at the gage center of the dynamically deformed torsional specimen of the low-carbon steel, but they were not observed in the dual-phase steel because localized deformation was alleviated by the increased strain hardenability. These results suggested that the ECAPed ultra-fine-grained dual-phase steel could be a good way to increase the fracture resistance under dynamic loading as the formation of adiabatic shear bands was reduced or prevented.
AB - Dynamic torsional deformation behavior of an ultra-fine-grained dual-phase steel fabricated by equal channel angular pressing (ECAP) was investigated and compared with that of an equal channel angular pressed (ECAPed) ultra-fine-grained low-carbon steel. Tensile and dynamic torsional tests were conducted on these two steels, and the deformed microstructures were observed to investigate the dynamic deformation behavior. The ECAPed low-carbon steel consisted of very fine, elongated ferrite-pearlite grains of 0.5 μm in size, and the ECAPed dual-phase steel consisted of ferrite-martensite grains of 1 μm in size. The dynamic torsional test results indicated that maximum shear stress of the dual-phase steel was lower than that of the conventional steel, but that fracture shear strain was higher in the dual-phase steel. Some adiabatic shear bands were observed at the gage center of the dynamically deformed torsional specimen of the low-carbon steel, but they were not observed in the dual-phase steel because localized deformation was alleviated by the increased strain hardenability. These results suggested that the ECAPed ultra-fine-grained dual-phase steel could be a good way to increase the fracture resistance under dynamic loading as the formation of adiabatic shear bands was reduced or prevented.
UR - http://www.scopus.com/inward/record.url?scp=36448970544&partnerID=8YFLogxK
U2 - 10.1007/s11661-007-9348-6
DO - 10.1007/s11661-007-9348-6
M3 - Article
AN - SCOPUS:36448970544
SN - 1073-5623
VL - 38 A
SP - 3007
EP - 3013
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
IS - 12
ER -