DENDRITIC GROWTH

Dendritic structures are the predominant microstructural constituents of solifidied alloys. The microstructural scales of dendrites, such as primary and secondary arm spacings, control the segregation pattern that largely determines the properties of the material. Within the past decade significant developments in understanding of dendritic structures have evolved through rigorous theoretical models and critical experimental studies in well characterised systems. These studies have resulted in the establishment of the criterion by which dendrite tip radius is selected under given experimental conditions. Furthermore, during the past decade, important advances have been made in predicting microstructural features that develop under rapid solidification conditions, and some key experimental studies have also been carried out to examine these microstructures. These studies have shown that the non-equilibrium conditions at the interface influence significantly the characteristics of dendrites formed under rapid solidification conditions. In this review the current status of dendritic growth phenomena are examined and critically assessed and key areas for the future directions of dendritic growth studies are suggested.