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 t hat largely determines the properties of the material. Within the past decade significant developments in understanding of dendritic structu res have evolved through rigorous theoretical models and critical expe rimental studies in well characterised systems. These studies have res ulted in the establishment of the criterion by which dendrite tip radi us is selected under given experimental conditions. Furthermore, durin g the past decade, important advances have been made in predicting mic rostructural features that develop under rapid solidification conditio ns, and some key experimental studies have also been carried out to ex amine these microstructures. These studies have shown that the non-equ ilibrium conditions at the interface influence significantly the chara cteristics of dendrites formed under rapid solidification conditions. In this review the current status of dendritic growth phenomena are ex amined and critically assessed and key areas for the future directions of dendritic growth studies are suggested.