Cast magnesium matrix composites reinforced with silicon carbide particles were investigated by using Raman microscopy. 3C, 4H and 6H polytypes of SiC particles were identified in the investigated composites. Additionally, Mg2Si compound was detected by Raman microscopy in the composites microstructure.
AM50/Mg2Si composites containing 5.7 wt. % and 9.9 wt. %. of Mg2Si reinforcing phase were prepared successfully by casting method. The microstructure of the cast AM50/Mg2Si magnesium matrix composites was investigated by light microscopy and X-ray diffractometry (XRD). The microstructure of these composites was characterized by the presence of α-phase (a solid solution of aluminium in magnesium), Mg17Al12 (γ-phase), Al8Mn5 and Mg2Si. It was demonstrated that the Mg2Si phase was formed mainly as primary dendrites and eutectic.
The preliminary results of the application of open-celled glassy-carbon foam (Cof) in magnesium matrix composites processed by the powder metallurgy method were presented. For the component consolidation, compaction with vertically-torsional vibration and hot-pressing were applied. For the material characterization, the microstructure examination LM and SEM with EDS was employed and also, the porosity and microhardness were measured. An influence of the carbon foam cells’ size on the composite porosity and microhardness was revealed. Additionally, a generation of a few micrometer thin and differently shaped MgO inclusions was observed. Differences in the oxide phase amount, size and shape in the magnesium matrix measured by the quantitative metallography method in the cross-sectioned composite elements were stated. With an increase of the distance from the composite roller top, an increase of the MgO content and microhardness was noticed.