Phenomenological Constitutive Model Of Magnesium Alloys Under Uniaxial Single-cycle Loading

Magnesium alloys exhibit great application potentials due to theirappreciably low density. The specific plastic behavior of magnesium alloyscharacterized by the plastic yielding asymmetry and complex hardeningevolution has been challenging numerical simulations implemented bytraditional constitutive models, which are consequently responsible for thefew current applications of the material in engineering.A phenomenological constitutive model based on the textureevolution theory is modified and optimized to study the stress-strainresponses of Magnesium alloys, i.e., AZ31B and AZ61A, which aresubjected to uniaxial single-cycle loading at room temperature. Three typesof microscopic plasticity deformation modes, i.e., slip, twinning anduntwinning, are conducted in the new constitutive model. Plastic yieldingasymmetry is captured with the initial non-zero back stress, and theevolution law of back stress and yield surface under uniaxial single-cycleloading are contributed to render the hardening behaviour of the material.A user subroutine UMAT is implemented in ABAQUS based on theimplicit integration and return mapping technique. Numerical simulationshows good agreements with experimental observations, which justifiesthe accuracy and efficiency of the model.