Characteristic Sizes for Exhaustion-Hardening Mechanism of Compressed Cu Single-Crystal Micropillars

The stress-strain response of Cu single-crystal compression micropillar containing initial dislocation network is investigated by three-dimensional discrete dislocation dynamics simulations. The results demonstrate that the stress-strain curves can be divided into three distinct types with increasing the sizes of micropillars: the three-stage exhaustion hardening, the multi-stage mixed hardening and the two-stage conventional forest hardening. The characteristic sizes of the micropillars is determined for the second type of the curves to be 500-700 nm.