Simulation of transmission electron microscopy images during tensile fracture of metal foils

Based on computer simulations, we examined a new mechanism of plastic deformation that has been proposed to operate in tensile fracture of metal foils. We constructed a Au crystal containing high concentration of vacancies and/or one subjected to large elastic tensile strain using embedded atom method (EAM) potential, and then calculated transmission electron microscopy (TEM) images of the crystal based on multislice method. Randomly distributed vacancies did not cause a large distortion in the crystal lattice, and did not affect the TEM image intensity appreciably unless the vacancy concentration exceeded several percent. Under a large elastic tensile strain of about 10% along 〈100〉, a periodic displacement of atoms whose amplitude was 10% of the atomic distance was induced, reducing the intensity of equal thickness fringe by about half. At around 15% tensile strain along 〈110〉, the crystal transformed from fcc to bcc structure, releasing the distortion of crystal lattice.