Influence of rare earth element erbium on microstructures and properties of as-cast 8030 aluminum alloy

Abstract

The modification behavior of different Er contents on the microstructures and properties of as-cast 8030 aluminum alloy was investigated by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), hardness test, electrical conductivity test and tensile property test. The results show that the addition of Er can refine the grains of as-cast alloy, which mainly promotes the nucleation of α -Al by causing constitutional supercooling and forming the Al₃Er nanoparticles as a heterogeneous nucleation core. Er can change the morphology of Al-Al₆Fe eutectic structure of the alloy, furthermore, Er can adsorb on the surface of the Al₆Fe phase to refine the Al₆Fe phase at eutectic structure. Er can improve the tensile properties, especially the elongation of as-cast 8030 aluminum alloy, which is attributed to the modification of Al-Al₆Fe eutectic and Al₆Fe phase.