Simulation of plastic deformation behaviors of bulk metallic glasses with micro- and nano-sized pores

摘要

Based on the phase-field model for deformations in bulk metallic glasses (BMG), shear banding in BMG with micro- and nano-sized pores is simulated and the thermo-plastic deformation behaviors are investigated. In the simulations, we use the free-volume concentration w0 at the pore surface as a measure of the roughness of the pore. We obtain the critical w0 when shear bands are initiated from the pore surface under different loading conditions. The effect of local heating due to shear banding on the critical w0 is also quantitatively determined. By considering the heat conduction around pores, shear banding around vacuum pores or pores filled with helium gas are found to be quite different. It is shown that the nano-sized pores act as sinks or sources for shear bands when the pore surfaces are tailored. The simulations indicate that engineering BMG with nano-sized pores is effective in improving their ductility.