Microstructure of SiCp-reinforced A356 cast Al metal-matrix composite

The microstructure of SiCp-reinforced A356 cast Al metal-matrix composite (MMC) has been investigated by means of transmission electron microscopy and energy-dispersive X-ray analysis. It is found that the MMC contains -SiC, ( + ₂) SiC composite, eutectic Si, GP zones of Si sequence, a new J phase and the amorphous phase Al_xSi₉Ca₂. The ₂-SiC is lathlike with a triclinic crystal structure having a=0.308 nm, b=0.305 nm, c=1.262 nm, = 93.8 °, = 90.0 °, and = 60.0 °. The J phase is bulk-like with a C-face-centred orthorhombic crystal structure having a = 0.680 nm, b = 1.170 nm and c = 0.826 nm.