Effects of Sc on the microstructures and mechanical properties of Al-Zn-Mg-Cu casting aluminum alloy

Effects of x%Sc (x=0.15, 0.30, 0.45) addition on the microstructures and mechanical properties of metal mold casting aluminum alloy Al-6.0Zn-2.8Mg-1.9Cu were studied. The results show that addition of Sc can reduce α(Al) grain size, modify α(Al)+η(MgZn₂) eutectic of the experimental alloy, and eliminate Al₇Cu₂Fe phase effectively. The addition of Sc element can improve the room temperature ultimate tensile strength of the experimental alloy, but has little effects on its plasticity. The room temperature UTS of the experimental alloy with the addition of 0.45% Sc reach 510 MPa, the maximum value, among the three Sc-content alloys. In addition, the high temperature tensile strength of the experimental alloy with addition of 0.30% Sc increased apparently comparing those with 0.15% and 0.45% Sc.