Research on the Long-Lasting and Remelting Properties of Nd Modification Effect on Cast Al-Mg₂Si Metal Matrix Composite

Abstract

<jats:p>The cast Al-Mg<jats:sub>2</jats:sub>Si metal matrix composite was prepared by metal model casting process with rare earth element Nd as the modificator. The effects of modification duration and remelting times on microstructure and mechanical properties of the composite were investicated by optical microscope (OM) and electronic universal testing machine. The results show that, after introducing a proper amount of Nd, both primary and eutectic Mg<jats:sub>2</jats:sub>Si in the Al-18 wt.%Mg<jats:sub>2</jats:sub>Si composite were well modified. The morphology of primary Mg<jats:sub>2</jats:sub>Si is changed from irregular or dendritic to polyhedral shape and the morphology of the eutectic Mg<jats:sub>2</jats:sub>Si phase is altered from flake-like to very short fibrous or dot-like. Moreover, the effect is of long-lasting and remelting properties. After the composite is modified for 300 min and remelted by 6 times, its primary and eutectic Mg<jats:sub>2</jats:sub>Si structures are still in modification state of small block and slices, and the tensile properties of the composite are not significantly affected.</jats:p>