Influence of strain rate on the compressive behavior of heterogeneous Cu/Ta multilayer: A molecular dynamics simulation study

Atomistic simulations are performed to study the compressive response of heterogeneous Cu/Ta multilayer at a wide range of strain rates. The results show that the yield strength and yield strain both increase with the increasing strain rate while the elastic modulus essentially remains invariant. The yield strength increases sharply when the strain rate exceeds the critical value of 10⁹s⁻¹. The yield of the sample at lower strain rate is primarily determined by the dislocation evolution in the hard phase (i.e. Ta layers), while dominated by the atomic amorphization of hard phase at higher strain rate. We show that the heterogeneous nanolayered composite exhibits a good deformation compatibility at lower strain rate but an obvious deformation incompatibility at higher strain rate.