Effect of trace Sr and Sc contents and ultrasonic vibration on the microstructure and mechanical properties of the A380 alloy

Abstract

The effect and mechanism of trace amounts of Sr and Sc in the A380 alloy under ultrasonic vibration (ultraviolet) modification on the microstructure and mechanical properties were investigated. The results showed that the primary α phase in A380 could be refined by adding Sr and Sc under ultraviolet treatment, the secondary dendrite spacing decreased significantly, and the thick dendritic shapes transformed to tiny disperse isometric crystals. The highest ultimate tensile strength (about 302 MPa) was obtained by adding 0.2 Sr+0.4 Sc (wt%) and applying ultraviolet treatment. The highest hardness (about 113 BHN) and elongation (about 4.65%) were obtained by adding 0.15% Sr+0.3% Sc and applying ultraviolet treatment, and the minimum grain size (about 27 μm) and maximum shape factor (around 0.8) were obtained for the same composition.