Twin thickness dominates the tribological properties of (111)-oriented nanotwinned copper with micro-scale grain

This study explored how the initial microstructure affects the friction and wear resistance of nanotwinned copper (Cu). We prepared (111)-oriented nanotwinned Cu films with varying mean twin thickness and tested their performance under dry-sliding conditions. Results revealed that twin spacing critically influences wear behavior: wider-spaced twins allow easier dislocation slip, leading to dynamic recrystallization within twin lamellae. In contrast, uniformly narrow twin spacing enhances the material's ability to adapt to friction-induced strain, forming a stable hybrid structure. This structure prevents dislocation movement and strain concentration, significantly improving wear resistance. This work highlights microstructure optimization as a key strategy for designing durable nanotwinned metals.