FURTHER OBSERVATIONS ON DENDRITIC GROWTH IN METALS

Abstract

The direction of dendrite growth has been determined as a function of crystallographic orientation for high purity tin and zinc, using a single crystal decanting technique. Measurements are reported on the rate of dendrite growth in lead, and the spacing between dendrite rows of a lead crystal for varying amounts of supercooling. The initial formation of dendrite stalks appears related to a cell structure observed on the exposed solid liquid interface.A mechanism of dendrite growth is advanced and compared with the experimental observations. It is shown that dendritic growth occurs only during the initial part of solidification. The remainder is a result of the nondendritic advance of a solid liquid interface with some thickening of the existing branches.