Channel Structures Formed in Copper Ingots upon Melting and Evaporation by a High-Power Electron Beam

A new phenomenon is described in this paper: the formation of macroscopic channel structures on the bottom of copper ingots which were used as the target for the synthesis of copper nanoparticles by high-power electron beam evaporation and condensation. In the synthesis experiment, the cylindrical copper ingot is melted and partially evaporated in a graphite crucible. The channel structures were originally observed after a series of nanoparticle synthesis experiments in varying conditions. In the present work, various process conditions are varied in order to recreate the structures and identify their mechanism of formation. Conditions in which the channel structures form and do not form are identified and interesting microstructures are observed near the channel structures.