TY - JOUR

T1 - In-situ characterization of transformation plasticity during an isothermal austenite-to-bainite phase transformation

AU - Holzweissig, M. J.

AU - Canadinc, D.

AU - Maier, H. J.

N1 - Funding information: Financial support by Deutsche Forschungsgemeinschaft within the Transregional Collaborative Research Center TRR 30 “Prozessintegrierte Herstellung funktional gradierter Strukturen auf der Grundlage thermo-mechanisch gekoppelter Phänomene” is gratefully acknowledged. D. Canadinc acknowledges financial support by the Turkish Academy of Sciences (TÜBA) within the Young Scientist Award Program (GEB?P).

PY - 2012/1/15

Y1 - 2012/1/15

N2 - This paper elucidates the stress-induced variant selection process during the isothermal austenite-to-bainite phase transformation in a tool steel. Specifically, a thorough set of experiments combining electron backscatter diffraction and in-situ digital image correlation (DIC) was carried out to establish the role of superimposed stress level on the evolution of transformation plasticity (TP) strains. The important finding is that TP increases concomitant with the superimposed stress level, and strain localization accompanies phase transformation at all stress levels considered. Furthermore, TP strain distribution within the whole material becomes more homogeneous with increasing stress, such that fewer bainitic variants are selected to grow under higher stresses, yielding a more homogeneous strain distribution. In particular, the bainitic variants oriented along [101] and [201] directions are favored to grow parallel to the loading axis and are associated with large TP strains. Overall, this very first in-situ DIC investigation of the austenite-to-bainite phase transformation in steels evidences the clear relationship between the superimposed stress level, variant selection, and evolution of TP strains.

AB - This paper elucidates the stress-induced variant selection process during the isothermal austenite-to-bainite phase transformation in a tool steel. Specifically, a thorough set of experiments combining electron backscatter diffraction and in-situ digital image correlation (DIC) was carried out to establish the role of superimposed stress level on the evolution of transformation plasticity (TP) strains. The important finding is that TP increases concomitant with the superimposed stress level, and strain localization accompanies phase transformation at all stress levels considered. Furthermore, TP strain distribution within the whole material becomes more homogeneous with increasing stress, such that fewer bainitic variants are selected to grow under higher stresses, yielding a more homogeneous strain distribution. In particular, the bainitic variants oriented along [101] and [201] directions are favored to grow parallel to the loading axis and are associated with large TP strains. Overall, this very first in-situ DIC investigation of the austenite-to-bainite phase transformation in steels evidences the clear relationship between the superimposed stress level, variant selection, and evolution of TP strains.

KW - Austenitization

KW - Bainite

KW - Digital image correlation

KW - Phase transformation

KW - Transformation plasticity

UR - http://www.scopus.com/inward/record.url?scp=84856587337&partnerID=8YFLogxK

U2 - 10.1016/j.matchar.2012.01.007

DO - 10.1016/j.matchar.2012.01.007

M3 - Article

AN - SCOPUS:84856587337

VL - 65

SP - 100

EP - 108

JO - Materials characterization

JF - Materials characterization

SN - 1044-5803

ER -