Silicon Carbide Dispersion Strengthening of Magnesium Using Mechanical Alloying Method

Abstract

To improve the mechanical properties of magnesium alloys, hot pressing was performed to produce a silicon carbide-dispersion-strengthened magnesium (SiC_p/Mg), in which SiC particles (SiC_p) were milled with pure Mg using an attritor ball mill to reinforce the Mg. In this study, the silicon carbide dispersion strengthening of magnesium using the mechanical alloying (MA) method was investigated. The experimental results are summarized as follows. By increasing the milling energy of the ball mill in which the pAl₂O₃/Mg MA powder of a previous study was fabricated, the density of the SiC_p/Mg was able to be increased to a value higher than that of the pAl₂O₃/Mg. The SiC_p/Mg is about two-thirds as dense as commercial aluminum alloys. The hardness of the SiC_p/Mg was about 1.5-fold that of the pAl₂O₃/Mg and exceeded that of AZ91D, which has the best mechanical properties of all the commercial Mg alloys. The highest value obtained was 95 HV. The bending strength of the SiC_p/Mg was better than that of the pAl₂O₃/Mg. The results of XRD analysis and SEM-EDAX of the SiC_p/Mg suggest that SiC_p is almost uniformly and finely dispersed in the Mg and that the grain size of the matrix becomes finer with the dispersion.