In situ development of AlBx/AA6060 and AA5083 alloys cast composites

Abstract

Abstract Al – AlBx (x = 2,12), AA6060 – AlBx (x = 2,12) and AA5083 – AlBx (x = 2,12) composites with 3 wt % AlBx particles were developed by in-situ reaction of molten aluminium and alloys (AA5083 and AA6060) with inorganic salt KBF4 at a temperature of 900 °C. The chemical reaction produces boron, which dissolves into the molten alloy and subsequently forms aluminium borides (AlB2 and AlB12). The thermodynamic properties of the reactions are calculated by HSC Chemistry 6.0 software. In the case of aluminium matrix the melt solidified in the crucible, between 980 °C and 200 °C, in order to develop the peritectic reaction AlB12 + 5Al(l) = 6AlB2. It was found that both in the case of aluminium and aluminium alloys the peritectic reaction occurs partially. The composites were characterised by SEM and XRD analysis. The stress-strain measurement showed 8% improvement towards the matrix alloys. The fracture features of composites were examined using SEM analysis. Ductile and brittle locally fractography is revealed. Composites exhibited a higher resistance to crack initiation than the matrix alloys. The results obtained in the experiments and analysis helps to clarify the mechanism of interaction between liquid aluminium and KBF4 at high temperatures.