Micromechanical modelling of twinning-induced plasticity steels

Abstract

To cite this version:Véronique Favier, D Barbier. Micromechanical modelling of twinning-induced plasticity steels. Scripta Materialia, Elsevier, 2012, 66, pp.972-977. <10.1016/j.scriptamat.2011 Abstract-The paper discusses a number of issues related to the development of a micromechanical polycrystalline model for twinning-induced plasticity steels: twinning features that have to be incorporated, identification procedure, description of the work hardening, role of the texture and the role of the interaction law between grains. Monotonous and reverse strain paths are investigated.

Performance and Characterization of TWIP Steels for Automotive Applications

“…For example, the contribution of DSA to the constitutive law can be considered as a purely additive term associated with isotropic hardening [77]. In contrast, hardening due to twinning results in significant intergranular stresses that lead to a strong Bauschinger effect and therefore requires a kinematic hardening contribution [28,72].…”

“…MATERIALS PERFORMANCE AND CHARACTERIZATION may occur with a minimal amount of plastic strain, and it has been observed to be activated for strains as low as 2 % [21,27,28]. Figure 5 shows that if C is low, more Mn is needed to prevent strain-induced transformation to martensite.…”

“…Texture plays a key role in twinning activation and kinetics [28]. The austenite grain orientation determines which twinning system is activated [6][7][8] and can often be related to the Taylor factor that links the resolved shear stress and strain to the tensile stress and strain of a polycrystal [8].…”

“…This is attributed to the increase in temperature and, hence, in the local SFE from the near-adiabatic heating conditions in the PLC bands enhanced by the low thermal conductivity of TWIP steels [38]. The evolved texture is still primarily controlled by the slip deformation, because the volume fraction of the twins is still relatively small in comparison [10,28,38].…”

On the evolution and modelling of lattice strains during the cyclic loading of TWIP steel

“…While the original EPSC model implements a Voce law and inherently accounts for the intergranular contribution to the back stress, a recent modification incorporating a non-linear kinematic hardening rule applied to the hardening of slip systems captures the effect of intragranular sources on the back stress [21]. In this regard, while the EPSC model has not been applied previously to the reverse loading of TWIP steels, Favier and Barbier [23] have recently attempted to simulate a reverse simple shear deformation via a translated field model. However, the model failed to capture the Bauschinger effect such that the flow stress was overestimated upon load reversal as the model accounted only for intergranular stresses but not for the intragranular stresses.…”