The effect of growth velocity on primary spacing of Al 3Fe dendrites in hypereutectic Al-Fe alloys

Abstract

Measurements of primary Al 3Fe dendrite spacing λ 1 as a function of growth velocity V in hypereutectic Al-Fe alloys are shown to be consistent with the relationship λG 1 2 V 1 4 =43±8 μm 3 4 K 1 2 s 1 2 for conditions sufficiently remote from those giving rise to extinction of growth of Al 3Fe dendrites by αAl−Al xFe eutectic. The downturn in λ 1G 1 2 that accompanies approach to this extinction condition is attributed to the associated sharp decrease towards zero of the difference in growth temperature between the competing constituents.