Constitutive modeling and strain hardening of CoCrFeNiAl_x high-entropy alloys

The mechanical behaviors of CoCrFeNiAlx (x = 0, 0.3) high-entropy alloys are investigated under quasi-static loading. Evolution of phases and microstructures is analyzed by using the x-ray diffraction, scanning electron microscope and transmission electron microscopy. A constitutive model based on the crystal plasticity theory is presented and an explicit algorithm is constructed for calculation. A dislocation-density-based description of hardening model is used to describe the strain hardening behaviors. Constitutive model validation is performed by comparing numerical results with experimental data. Evolution of dislocation density with various slip systems during plastic deformation is established to reveal the effect of Al addition on the CoCrFeNi based HEAs.