In this paper, the tensile deformation process of single crystal copper microstructure is simulated by molecular dynamics using a three-dimensional model, where the Newton equations of motion are solved utilizing the Morse potential. Cohesive energy, bulk modulus and lattice constant of material are used to evaluate the three parameters of Morse interatomic potential for single crystal copper. To reduce the limit size effect the rigid boundary condition is employed and to control the tensile deformation at a low temperature the velocity scaling method is used. Two tensile models with and without crack are simulated separately using the approach described above. From the point of view of the energy evolution, the mechanism of deformation and fracture are illustrated. The failure strength of single crystal copper obtained by the simulation is 24.1 GPa in the model without crack and 20.6GPa in the model with crack respectively. The Griffith's fracture theory is used to make it clear that failure the strength of ideal microstructure is greatly higher than that of bulk material with defects.
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