Kinetics of bismuth melt penetration along copper grains

Abstract

The method of direct visual study in situ by means of light microscope LEICA-L2 was used for examination of the channel development kinetics for bismuth melt through penetration along grain boundaries and triple joint group of grains in thin (from 120 to 500 μm) polycrystalline copper samples. Copper (99,995 wt.%) and bismuth (99,999 wt.%) were used as initial metal materials for the studies. Copper samples had average grain size of 30–50 μm. In their studying after holding in contact with bismuth melt at temperatures of 490–600 °C, the photographic images showing the Bi penetration through Cu-plates as well as the image of liquid metal channel network on cross-sections of samples have been obtained. Temperature dependence of melt penetration rate through polycrystalline copper plates and the effective activation energy of Bi penetration process along grain boundaries are obtained.