Micromechanical modelling of the elastoplastic behaviour of metallic material under strain-path changes

Abstract

International audienceA two-level homogenization approach is applied for the micromechanical modelling of the elastoplastic material behaviour during various strain-path changes. A mechanical description of the grain is developed through a micro-meso transition based on a modified elastoplastic self-consistent approach which takes into account the dislocation evolution. Next, a meso-macro transition using a self-consistent model is used to deduce the macroscopic behaviour of the polycrystal. A correct agreement is observed between the simulations and the experimental results at the mesoscopic and macroscopic levels

Experimental and Numerical Analysis of Mechanical Behaviour of AISI 316L Austenitic Stainless Steel: Two Level Homogenization – Neutron Diffraction

“…with: , and (6) corresponds to the rate of increase of dislocation density inside the walls on the system g. This term is responsible for the creation and the development of the cell structure. This flux consists of dislocations that glide towards walls through the applied stress.…”

“…During the plastic regime, the variation of the cell interior volume fraction for a grain I is considered as a function of the accumulated slip through the following empiric relation [6]:…”

Bauschinger Effect in an Austenitic Steel: Neutron Diffraction and a Multiscale Approach

“…The formation of a dislocation microstructure, responsible for intragranular heterogeneities, is insufficiently represented through hardening laws. [3] In this case, the modelling effort must be focused on the description of grains interactions and their local behavior. If the intergranular heterogeneities prevail at low and monotonic loading, they gradually give rise to intragranular heterogeneities during complex loading.…”

“…In previous works, [3,23] based on the approach originally proposed by Muller et al, [4,5] the present authors have extended the elastoplastic self-consistent model (EPSC) by incorporating more details of the microstructure at the grain scale. The grain was considered as a two-phase material (dislocation walls and cells).…”

“…A micro-mechanical description of a single crystal was developed through a micro-mesoscopic transition using Kro¨ner [23] and self-consistent [3] approaches. Therefore, the grain behavior was calculated from phases (cell and wall).…”