Crystal plasticity finite element simulations of pure bending of aluminium alloy AA7108

Abstract

The crystal plasticity finite element method (CP-FEM) is used to investigate the influence of microstructure on the bending behaviour of the heat treatable aluminium alloy AA7108. The study comprises two materials obtained from the AA7108 aluminium alloy by different thermo-mechanical treatments. The first one is an as-cast and homogenized material consisting of large grains with random texture, while the second one is a rolled and recrystallized material having refined grains with weak deformation texture. The behaviour of the two materials in plane-strain bending is investigated numerically and compared qualitatively to existing experimental data. The crystallographic texture and grain morphology of the materials are explicitly represented in the finite element models. The numerical results display a strong effect of the grain morphology on the bending behaviour, the surface waviness and the development of shear bands. These results are consistent with the experimental observations. The simulations further indicate that crystallographic texture affects the bending behaviour of the rolled and recrystallized material.

An analysis of macro- and micro-scale residual stresses of Type I, II and III using FIB-DIC micro-ring-core milling and crystal plasticity FE modelling

“…The elastic and plastic parameters of the material studied were taken from literature: anisotropic stiffness coefficients ‫ܥ‬ ଵଵ = ‫,ܽܲܩ801‬ ‫ܥ‬ ଵଶ = ‫ܽܲܩ16‬ and ‫ܥ‬ ଶଶ = ‫ܽܲܩ92‬[55], and the Critical Resolved Shear Stress (CRSS) ߬ = ‫ܽܲܯ9.241‬[56]. The hardening parameters were calibrated in the course of simulation to obtain agreement with macro-scale model behaviour.Periodic and symmetry conditions were imposed to the RVE as boundary conditions.…”

Heat-Treatable Aluminum Alloys: Three-Point Bending

“…In the finite element simulations presented by Saai et al (12) and Mattei et al (32), it is shown that a larger grain size in a material with equi-axed grains leads to an earlier formation of macro shear bands and an increase in surface waviness. In the work by Lievers et al (9) the influence of iron content on the bendability has been investigated.…”

“…Since many factors influence the mechanical behavior of a material, the effect of texture is more easily cultivated and studied applying crystal plasticity theory, either Taylor-based models (e.g. (11,48)) or crystal plasticity finite element models (CP-FEM) (12). Dao and Li (49) concluded that surface roughening (orange peel appearance) work as initiation spots for the shear band formation.…”

“…An extruded profile or rolled sheet will not behave in an isotropic way during bending as it is assumed for many of the old models (8). In later years there has been more focus on trying to describe and model what happens in the material during bending from a phenomenological perspective (8)(9)(10)(11)(12).…”

Comparative Study of the Effects of Galvanic Corrosion on the Strength and the Failure of Aluminium and Stainless Steel Bolted Joints

“…8. However, it must be mentioned that aluminium deformations are anisotropic and involve complex mechanisms, where the mechanical response depends on the combined effects of microstructure and loading path (Saai et al, 2013;Saai et al, 2011a;Saai et al, 2011b). The simplified model and calibration process of aluminium based on tensile test might affect the prediction accuracy of aluminium model in complex load scenario and state of stress.…”