Finite Element Simulation of the Elastoplastic Deformation of Tricrystals: Comparisons with Experiments and Analytical Solutions

Abstract

The deformation of crystalline aggregates is very often heterogeneous both at an intergranular and intragranular scale. The experimental study of special aggregates made of a very small number of grains limited by grain boundaries of a simple geometrical nature and of well known orientations has allowed a detailed characterization of these heterogeneities. In this particular instance, we consider copper tricrystals with one or two triple junctions which are deformed by tension up to a few percent overall plastic strain. These samples are made of a single layer of grains of centimetric sizes, with grain boundaries orthogonal to a common plane. The overall size of a sample is 40×14×3 mm³. The heterogeneities of deformation lead to the formation of intragranular domains where different glide systems are active. A finite element model is used in order to simulate the deformation of these aggregates. It allows the computation of the final orientations of the crystallites and the misorientations, the slipmagnitudes on the active systems in different regions, the internal stresses state and the local strains. These values are then compared with results obtained through observations and analytical modeling.