Modeling of Plastic Strain-Induced Martensitic Transformation for Cryogenic Applications

Abstract

A simplified model of martensitic transformation in stainless steels at cryogenic temperatures is proposed. The constitutive modeling of plastic flow under cryogenic conditions is based on the assumption of small strains (⩽0.2). The hardening law for the biphase material (α′ martensite platelets embedded in the γ austenite matrix) has been obtained from the Mori-Tanaka homogenization. A mixed hardening with combined isotropic and kinematic contributions is proposed. The constitutive model, containing a reasonable number of parameters, has been numerically implemented and checked with respect to experimental data. Finally, the model is applied to compute the martensite evolution in thin-walled corrugated shells designed for cryogenic temperatures (mechanical compensation system of the Large Hadron Collider at CERN).

A constitutive model for analyzing martensite formation in austenitic steels deforming at high strain rates

“…Fisher et al (2000) proposed a constitutive description of SIMT taking into account both the influence of transformation induced plastic strain and the influence of shear (orientation effect) on irreversible deformation. Garion and Skoczén (2002) proposed a simplified mar tensite evolution law to describe only the linear part of the sigmoidal curve, which has proven to be appropriate for cryo genic applications (Egner and Skoczén, 2010). Oberste Brandenburg and Bruhns (2004) described the behavior of TRIP steels based on a tensorial description of the thermodynamic driving force for the phase transformation.…”

Plastic strain induced damage evolution and martensitic transformation in ductile materials at cryogenic temperatures

“…However, a considerable number of parameters have to be identified for these models. In the present paper, a simplified model -developed by Garion and Skoczen [2] for cryogenic applications -is applied. The volume fraction of martensite [ can be presented in the following form:…”

“…2): simplified law of evolution of the martensite content has been proposed (cf. [2]) for the phase II under the following form:…”

“…The evolution of the volume fraction of martensite is governed by a kinetic law based on the accumulated plastic strain (cf. [2]). Both of these irreversible phenomena, associated with the dissipation of plastic power, are included into the constitutive model of stainless steels at cryogenic temperatures.…”

“…[2]). The constitutive model is tested on the thinwalled corrugated shells (bellows expansion joints), used in the interconnections of the LHC at CERN, subjected to thermo-mechanical loads at cryogenic temperatures.…”