Simulation of Large-Strain Tensile Necking in Single-Crystal Copper Specimens

The mechanical behavior, the necking process and the geometry of the neck in rectangular cross-section single-crystal copper specimens under macroscopic uniaxial large-strain tensile conditions were numerically simulated and analyzed using the classical Chaboche combined hardening model and the crystal plasticity constitutive model including the effect of back stress. The simulation results show that, although the classical Chaboche model can simulate the load–displacement curve during the tensile process, it cannot simulate the geometric shape change in the cross-section of the single-crystal copper specimen during the necking process. However, simulation using the crystal plasticity model can not only accurately simulate the macroscopic load–displacement mechanical curves of specimens with different crystal orientations (considering eight off-axis states) but also successfully displays the complex necking morphologies, consistent with experimental observations in the literature for various orientations. The research indicates that the classical Chaboche model lacks the ability to describe the deformation characteristics of single-crystal copper specimens; meanwhile, the crystal plasticity model has a significant advantage in simulating the necking process and characteristics of single-crystal materials under slip mechanisms and can effectively capture the differences in necking morphology caused by the crystal orientation, revealing, to a certain extent, the plastic deformation mechanism in single-crystal metallic materials.