TY - JOUR
T1 - Strain rate dependent dynamic mechanical response of bainitic multiphase steels
AU - Shakerifard, Behnam
AU - Galan Lopez, Jesus
AU - Taboada Legaza, Mari Carmen
AU - Verleysen, Patricia
AU - A.I. Kestens, Leo
PY - 2019
Y1 - 2019
N2 - Bainitic steels, as a third generation of advanced high strength steels, are potential steel grades for automotive applications. Two grades of bainitic steels with low and high silicon content, with three different thermal treatments per grade and therefore different second phase constituents, are examined under quasi-static and high strain rate deformations. Microstructures are studied by advanced characterization techniques, including X-ray diffraction and scanning electron microscope equipped with an electron backscatter diffraction detector. Subsequently, the quasi-static and dynamic mechanical responses of the steels are correlated to the microstructures. A positive effect of the strain rate is observed for all the examined materials: when the strain rate is increased, both the tensile stress and deformation levels increase, thus also the energy absorption capacity. However, it is shown that the higher the fraction of second phase constituents, the lower the effect of strain rate becomes. In addition, the grain size directly correlates to the strain rate effect too. The phenomenological hardening model of Johnson-Cook is used to simulate the quasi-static and dynamic flow behaviors, allowing to quantify the strain rate sensitivity for each material. A comprehensive literature survey on the strain rate sensitivity of various steel grades reveals that steels with higher strength demonstrate a lower strain rate sensitivity factor. This trend can be approximated by a power law function which clearly is followed by the materials under consideration in this study.
AB - Bainitic steels, as a third generation of advanced high strength steels, are potential steel grades for automotive applications. Two grades of bainitic steels with low and high silicon content, with three different thermal treatments per grade and therefore different second phase constituents, are examined under quasi-static and high strain rate deformations. Microstructures are studied by advanced characterization techniques, including X-ray diffraction and scanning electron microscope equipped with an electron backscatter diffraction detector. Subsequently, the quasi-static and dynamic mechanical responses of the steels are correlated to the microstructures. A positive effect of the strain rate is observed for all the examined materials: when the strain rate is increased, both the tensile stress and deformation levels increase, thus also the energy absorption capacity. However, it is shown that the higher the fraction of second phase constituents, the lower the effect of strain rate becomes. In addition, the grain size directly correlates to the strain rate effect too. The phenomenological hardening model of Johnson-Cook is used to simulate the quasi-static and dynamic flow behaviors, allowing to quantify the strain rate sensitivity for each material. A comprehensive literature survey on the strain rate sensitivity of various steel grades reveals that steels with higher strength demonstrate a lower strain rate sensitivity factor. This trend can be approximated by a power law function which clearly is followed by the materials under consideration in this study.
KW - Advanced high strength steels
KW - Bainite
KW - Constitutive modelling
KW - Hopkinson tensile bar
KW - Microstructure
KW - Strain rate sensitivity
UR - http://www.scopus.com/inward/record.url?scp=85059327969&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2018.12.105
DO - 10.1016/j.msea.2018.12.105
M3 - Article
AN - SCOPUS:85059327969
SN - 0921-5093
VL - 745
SP - 279
EP - 290
JO - Materials Science and Engineering A
JF - Materials Science and Engineering A
ER -