Penetration of liquid tin along grain boundaries and triple grain-boundary junctions of aluminum

Abstract

A new procedure for investigation of liquid-metal etching grooves that form owing to wetting and penetration of the liquid phase along the triple grain-boundary junctions (triple junction) and grain boundaries in the Al-Sn system is described. The investigations were carried out by the method of layer-by-layer polishing of the end surface of the wetted sample. The obtained slices were investigated by methods of optical and electron scanning microscopy. It was shown that the groove depth is virtually invariable along a single grain boundary and increases as the groove approaches the triple junction. The penetration depth of Sn along the triple junctions is much larger than along the grain boundaries. It is shown that, owing to wetting processes in the triple junction, as in the grain boundaries, the Sn-based alloy is formed.