Microstructure characterization on the formation of in situ Mg2Si and MgO reinforcements in AZ91D/Flyash composites

5 wt.% and 100 μm in size of fly ash cenosphere particles were incorporated in AZ91D Mg alloy to fabricate in situ Mg2Si and MgO reinforced AZ91D/Flyash composites by means of compocasting method. The in situ Mg2Si and MgO were identified using X-ray diffraction (XRD), energy dispersive spectrometer (EDS), and thermodynamic analysis. The results show that the cenosphere particles distributed homogeneously in the matrix alloy. Moreover, most of the cenosphere particles were filled with the matrix alloy. The preliminary discussion was carried out on the growth mechanism of the in situ Mg2Si.

Research highlights▶ The in situ composites AZ91D/Flyash by incorporating fly ash cenospheres were firstly fabricated by means of comp-casting method. ▶ In situ Mg2Si and MgO compounds in the composite formed from fly ash cenospheres were firstly investigated.