Microstructure of fly ash cenosphere/AZ91D composite during solution treatment at 380-420℃

Abstract

The fly ash cenosphere/AZ91D (FAC/AZ91D) composites containing 5 wt.% and 100 µm in size of fly-ash cenosphere particles were fabricated by means of the compcasting method. The microstructures of the as-cast samples and the effect of the solution treatment at 380℃, 400℃, and 420℃ for 16 h on the microstructures of the samples were investigated by using of OM, SEM, XRD and EDS. The results showed that the cenospheres distributed homogeneously in the Mg alloy, and were almost filled with Mg alloy. The main interfacial phase between the cenospheres and AZ91D Mg alloy was identified as MgAl2O4 according to XRD, EDS and thermodynamic analysis. Mg2Si particles tended to be spheroidized via the solution treatment and the β phase (Mg17Al12) dissolved completely at 400℃.

Keywords

• composite materials
• liquid–solid reactions
• quenching
• microstructure