Molecular Dynamics Simulation of the Effects of Void Defect on the Tensile Deformation Behavior of α-Fe

Abstract:

To further investigate the effects of void defect on the plastic deformation behavior of α-Fe under tensile load, the molecular dynamic models of the α-Fe samples with the void defects were established and related simulations under uniaxial tension were carried out for a series of models. The results show that overall, the deterioration of tensile mechanical properties of the sample with void is positively related to the void size. The larger the void size, the easier the occurrence of plastic deformation stage for sample. Overall, the Young's modulus, yield stress, ultimate tensile strength and tensile elongation of the samples containing void decrease with increasing the radius of void. The plastic deformation mechanism is of a mixture of the tensile stress-induced structural phase transition and the dislocation slip. However, the characteristics of stress-strain curves change significantly with increasing the radius of void, the plastic yield stage and strain hardening stage of the sample become shorter, and the strain hardening stage even vanishes. The research deepens the understanding of the effects of void defect on the mechanical properties and plastic deformation mechanisms of metals and lays a useful foundation for the subsequent analysis and study of the physical and mechanical properties of polycrystalline α-Fe materials under various conditions.