Effect of Intrinsic factors on primary dendrite arm spacing in Ni-base binary alloys

Abstract

Since the equilibrium distribution coefficient and solidification temperature range are determined when the initial solute concentration of a binary alloy is decided, researchers have not directed their attention to the effects of them on primary dendrite arm spacing, whereas there have been many studies on the effects of solidification rate and temperature gradient on primary dendrite arm spacing in past decades. In the present study, Ni-Al and Ni-Nb binary alloys were solidified unidirectionally in order to investigate the effects of intrinsic factors such as equilibrium distribution coefficient and solidification temperature range on primary dendrite arm spacing. It was found that the primary arm spacings of them increased linearly with the fourth root of the product of the equilibrium distribution coefficient and the solidification temperature range in the equilibrium solidification of each alloy. This result agrees with results obtained using previously proposed theoretical equations.