Effect of V on the microstructure and mechanical property of Al-Mg-Si alloy by adding Al3V phase

The effect of V microalloying on the microstructure and mechanical properties of Al-Mg-Si wrought aluminum alloy by adding the Al-4V (wt.%) master alloy containing the single type of Al3V phases was studied by optical microscope, scanning electron microscope and energy spectrum analysis. The results showed that adding V into the Al-1.6Mg-1.2Si (wt.%) alloy by means of Al3V phases significantly refined the as-cast alloy structure and reduced the grain size by 3.30%. During homogenization heat treatment, dispersed spherical V-containing phase precipitated from the matrix and strongly inhibited the recrystallization grain growth during the T6 heat treatment. The mechanical properties of T6 alloy was improved significantly when the minor V was added by means of Al3V phases, with the tensile strength (UTS) and yield strength (YS) increased by 1.21% and 2.42% respectively while elongation (EL) increased significantly by 130%

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

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