PREDICTION OF AVERAGE SPACING FOR CONSTRAINED CELLULAR DENDRITIC GROWTH/

Since 1990, it has been gradually understood that there exists an allo wable range of cellular/dendritic spacings during unidirectional solid ification. The lower and upper limits of the allowable range are very sharp at the same current growth condition, while the average spacing for cellular/dendritic arrays depends on the history of variation of s olidification parameters. The present work puts forward a novel numeri cal model to predict the ultimate average spacing for constrained cell ular and dendritic growth, according to the characteristics of unstead y-state evolution of cellular and dendritic arrays. Our analysis consi dering the history-dependent selection of the average spacing for cell ular/dendritic arrays, we find - with no adjustable parameters - good agreement with experimental results obtained in different alloys and i n different velocity histories.