Armin Abedini

Microstructural and Numerical Investigation on the Shear Response of a Rare-Earth Magnesium Alloy Sheet

Shear tests were performed on an anisotropic rare-earth magnesium alloy rolled sheet (ZEK100-O) to study the constitutive plastic behaviour of the material under quasi-static conditions at room temperature. The shear response was characterized in three orientations by setting the shear loading direction at 45°, 90°, and 135° with respect to the rolling direction. Each orientation displayed unique trends in terms of yielding and the work hardening rates. Electron Backscattered Diffraction (EBSD) analysis was used to analyze the microstructure of the deformed samples and to determine the twinning modes and twin fraction in each specimen. The results suggest that these parameters have a significant impact on the constitutive behavior of the material. Furthermore, the viscoplastic self-consistent twinning-detwinning (VPSC-TDT) model was used to understand the activity of the various deformation mechanisms and validate the experimental observations.

The Influence of Multiple Inclusions on the Cauchy Stress of a Spherical Particle-Reinforced Composite Under Uniaxial Loading

This paper investigates the influence of multiple inclusions on the Cauchy stress of a spherical particle-reinforced metal matrix composite (MMC) under uniaxial tensile loading condition. The approach of three-dimensional cubic multi-particle unit cell is used to investigate the 15 non-overlapping identical spherical particles which are randomly distributed in the unit cell. The coordinates of the center of each particle are calculated by using the Random Sequential Adsorption algorithm (RSA) to ensure its periodicity. The models with reinforcement volume fractions of 10%, 15%, 20% and 25% are evaluated by using the finite element method. The behaviour of Cauchy stress for each model is analyzed at a far-field strain of 5%. For each reinforcement volume fraction, four models with different particle spatial distributions are evaluated and averaged to achieve a more accurate result. At the same time, single-particle unit cell and analytical model were developed. The stress-strain curves of multi-particle unit cells are compared with single-particle unit cells and the tangent homogenization model coupled with the Mori-Tanaka method. Only little scatters were found between unit cells with the same particle volume fractions. Multi-particle unit cells predict higher response than single particle unit cells. As the volume fraction of reinforcements increases, the Cauchy stress of MMCs increases.Copyright