Effect of cooling rate on the size fluctuation of V-containing phases in Al-V master alloys

Abstract

To investigate the relationship between the solidification cooling rate and the size fluctuation of different V-containing phases, Al-4 wt. % V master alloys with various V-containing constituents were prepared at different cooling rates carried out by a wedge-shaped water-cooled copper mold, a graphite mold and a refractory mold at 1050°C, respectively. The variance of lognormal density function was used to characterize the size fluctuation of V-containing phases quantitatively. The results show that the largest size difference of both Al10V phases and Al3V phases is simultaneously present in the ingot prepared by the average solidification cooling rate of 2°C·s-1, while the smallest difference of Al10V phases in size is present in the ingot prepared by the average solidification cooling rate of 271°C·s-1. The size fluctuation of the Al3V phases first increases slightly and then decreases with increasing average solidification cooling rate in the range of 30~195°C·s-1.