Competing failure modes in void and inclusion NiCoCrFeCu alloy under tensile simulation using molecular dynamic

Abstract

This study exhibits dual effects from the parallel existence of inclusion and void on mechanical characteristics and deformation response for NiCoCrFeCu alloy based on an MD simulation of a tensile test. The pure Cu-inclusion and the defect rate 1.0 reinforce the strength of NiCoCrFeCu HEA, while pure void causes damage quickly of HEA. The nuclear deformation forms at the void root and boundary between the inclusion and workpiece for defect samples, which occurs in random zones for monolithic pieces. The deformation density for the sample combined void and inclusion is always the lowest because the boundary prevents the fusion between the hole-induced and workpiece-induced deformation. The defect rates are a critical factor in deciding the phase transition and deformation development during the strain stages, and the defect rate of 1.0 is the ladder. The tensile strength and strain energy increase as the defect rates increase from 0.43 to 1, then enormously decrease as the defect rate to 1.5, while Young’s modulus declines with an increase in defect rate. Moreover, the results also show that the effect of the void position and the divided number of voids with the same void volume in each material sample is severe. The tensile strength and Young’s modulus increase with the increase of the void number; the model with two voids in the X direction is subjected to higher stress than those with two holes in the Y direction. Finally, the mechanical parameters, such as the tensile strength and Young’s modulus, all decrease as the void radius and inclusion radius increase, and the sample can enhance elongation when adding an inclusion with a radius of 30 Å. The occupation of the twin boundary interferes with the development of dislocation, reducing the total dislocation length.