Molecular dynamics of viscoplasticity in β-tin lattice and grain boundary

Viscoplasticity in β-Sn lattice and grain boundaries is studied at the atomic level. Two kinds of β-Sn lattice structures are studied. Model I is the perfect β-Sn lattice structure in [0 0 1] orientation. Model II is β-Sn lattice structure with several symmetric tilt grain boundaries. The β-Sn models are simulated by Molecular Dynamics (MD) simulation package, LAMMPS. Modified Embedded-Atom Method (MEAM) is employed for the β-Sn potential. In order to study the effects of strain rate on β-Sn, a range of strain rates are applied. Simulation is conducted for NVT ensemble. Thermal effects are also studied. The results of molecular dynamics simulations are compared with experimental data of viscoplastic behavior of bulk tin.

► Viscoplasticity in β-Sn lattice and grain boundaries is studied at the atomic level.
► Shear of β-Sn lattice shows a new plastic behavior: tilt, breakdown, and recovery.
► Thermal and strain-rate effects in this study agree well with empirical result.
► High strain rate in grain boundary structure leads expansion of grain boundary width.
► Stress exponent in creep equation varies by temperature and crystal orientation.