Low-temperature annealing effects on friction and wear performance of nanotwinned copper dry sliding against zirconia

Abstract

To elucidate the influence of structural parameters beyond twin thickness on the tribological behavior of nanotwinned metals, we fabricated a series of nanotwinned copper (NT-Cu) films with almost the same average twin thickness using direct current electroplating, followed by annealing at temperatures below the de-twinning point. Subsequently, we assessed their tribological performance under dry sliding conditions against zirconia balls and observed a significant reduction in both the coefficient of friction and wear rate of the NT-Cu films post-annealing. Through a comparative analysis of the microstructures of NT-Cu before and after annealing, coupled with an examination of the worn subsurface microstructure, we identified the contributions of grain size and texture to the reduced friction and wear rate of the NT-Cu films. This study sheds light on the role of the initial microstructure in dictating the tribological properties of nanotwinned metals.