Atomic-scale insights into the strength and plasticity enhancement of Ni-based superalloys with refinement dispersion of precipitates

The effect of dispersion distribution of the precipitated phase (gamma' phase) on strength and plasticity at atomic scale in Ni-based superalloys with 15 % volume fraction of gamma' phase and diameters of 10 and 30 nm at roomtemperature were revealed by molecular dynamics simulation. The gamma' phase dispersion refinement can effectively suppress crack propagation, and enhances its strength and plasticity. The increased number of phase boundaries for dislocation nucleation has improved its strength. The small-sized gamma' phase boundaries promote dislocation nucleation and emission to reduce the stress concentration. Additionally, the competitive mechanism ISF and phase transition can further enhance the plasticity.