Effect of Capacitor Discharge Welding on Single-Crystal Metals

Abstract

The objective of this study was to investigate the use of capacitor discharge welding (CDW) as a suitable technique for joining metal single crystals by studying the effect of CDW on the microstructure of single-crystal copper. According to solidification theory, single-crystal formation requires high thermal gradients and moderate solidification rates. Therefore, an initial analysis was performed to determine if single-crystal CDW would result in a single-crystal microstructure. Joints were made using samples with joining surfaces at 0°, 15°, 30°, and 45° to the (111) crystal plane. Results show that single-crystal copper can be joined using CDW without the formation of voids and grain boundaries at the weld centerline. Average etch-pit densities after CDW are lower than those reported in the literature for single-crystal copper, suggesting minimal microstructural disruption. Crystal orientation does not seem to have any effect on fusion zone thickness or etch-pit density. Further work is needed to evaluate the effect of crystal orientation on void content in single-crystal copper welds made by CDW.