Molecular dynamics simulation and micropillar compression of deformation behavior in iridium single crystals

摘要

The compression behaviors of iridium single crystals with different crystalline orientations were investigated by micropillar compression tests and molecular dynamics(MD) simulations.The results indicated that the deformation process of iridium single crystals with [100]and [110] orientations was presented as the stacking faults expansion and the formation of Lomer-Cottrell locks.And the occurrence of Lomer-Cottrell locks was considered as the interaction of stacking faults on {111} planes by MD simulations.The evolution of crystal structure in compression indicated that the Lomer-Cottrell locks might contribute to the large plastic deformation of iridium single crystals.Moreover,the deformation features in MD simulations showed that the elastic modulus(E) and yield stress(σ_s) of iridium single crystals were significantly influenced by the temperature.The elastic modulus and yield stress gradually decreased with an increased temperature for all orientations.Meanwhile,the single crystal with a closely spaced lattice structure exhibited superior mechanical properties at a same temperature.