Electron microscopy studies of interfacial reaction in a (SiCw+B4CP)/ZK60A hybrid composite

The interfacial reaction in the (SiCW+B4CP)/ZK60A composite was studied to get an insight into the nature of reinforcement/matrix interfaces. The interfacial reaction occurred at the SiC/Mg and B4C/Mg interfaces during composite fabrication. MgB2 and MgO were formed at the SiC/Mg interfaces through the chemical reaction, B4C+O2→B2O3+CO2 and B2O3+Mg→MgB2+MgO. There existed a consistent orientation relationship (OR) among the three phases, [110]SiC∥[110]MgO∥[11 2̄ 0]MgB2 (1̄ 1 1̄)SiC∥(1̄ 1 1̄)MgO∥(000 1̄)MgB2. A facetted MgO nanocrystalline particle was also found at the SiC/Mg interfaces and should be cubo-octahedral in shape. MgB2 was found at the B4C/Mg interfaces. However, there is no consistent OR between the two phases. SiC is more stable than B4C in the (SiCW+B4CP)/ZK60A hybrid composite.