Influence of Carbon and Scandium on Structure of Metastable Al$_3$Mg Phase and Properties of SPS-Composites

Abstract

The solid dispersant (graphite) and additional alloying by scandium effects on the intermetallic compound formation in the Al-Mg system under mechanical alloying are studied. As found, the scandium additive significantly accelerates the metastable intermetallic Al 3 Mg phase formation in (75% at. (Al + 2% wt. Sc)-25% at. Mg)/5% wt. C powder mixture compared to the (75% at. Al-25% at. Mg )/5% wt. C one. The synthesized powder composite, containing metastable Al 3 Mg phase and solid solution based on aluminium, is consolidated by the spark plasma sintering (SPS) method. The phase composition, structure, and hardness of the SPS sintered samples are determined by X-ray diffraction, scanning electron microscopy, and indentation by the Vickers indenter. The hardness of samples formed after spark plasma sintering is in the range of 175-212 HV and significantly exceeds the hardness of duralumin (124 HV).