Fig. 1

Stress–strain curves and average flow stress from molecular dynamics simulations of nanotwinned Pd. a, c Simulated stress–strain relations of nanotwinned Pd samples with grain sizes of a d = 10 nm and c 20 nm, and twin thickness varying from λ = 0.67 to 2.23 nm at different temperatures T = 1, 300, 800, and 1400 K. b, d Average flow stress of nanotwinned Pd samples with grain sizes of b d = 10 nm and d 20 nm at different temperatures. The average flow stress is calculated for strains ranging from 6 to 10% for each sample. A transition from hardening to softening behavior is observed by increasing the temperature. The average flow stress increases continuously by decreasing the twin thickness at lower temperatures 1 and 300 K, while it decreases at 1400 K when the twin thickness is reduced. Error bars represent the standard deviation from statistical analyses