Grain growth in pulse reverse electrodeposited copper foil: Contrasting effects of duty cycle during deposition and annealing

The present study reports the opposite effects of the duty cycle in a pulse reverse electrodeposited copper foil during electrodeposition and further annealing. With increasing duty cycles from 60 to 90 %, while the average grain size decreases from 8.5 & PLUSMN; 6 mu m to 4 & PLUSMN; 2.7 mu m, the fraction of twin boundaries and crystallite size increase continuously in the as-deposited conditions. After annealing at 1050 ?, the average grain size increases, and the fraction of coherent twin boundaries reduces with an increase in the duty cycle. The differences in the anodic period at different duty cycles regulate the twin probability and grain size during deposition, while the stored energy governs the twinning probability during annealing. Interestingly, after annealing for 6 h, significant fractions of interconnected twinned regions are visible in all Cu foils. These results show that it is possible to maintain a high fraction (> 60 %) of twin boundaries in high-temperature annealed Cu foils.

Automated summary

The present study examines the effects of duty cycle in pulse reverse electrodeposited copper foil during electrodeposition and annealing. Results show that increasing duty cycles lead to a decrease in grain size and an increase in twin boundaries and crystallite size. However, after annealing, the average grain size increases and the fraction of twin boundaries decreases with an increasing duty cycle. The differences in anodic period and stored energy play important roles in regulating twin probability and grain size during the deposition and annealing processes.