The crystallographic orientation relationship between Al₂O ₃ and MgAl₂O₄ in the composite material Al ₂O₃/Al-Mg-Si alloy

The formation mechanism of spinels on Al₂O₃ particles in the Al₂O₃/Al-1.0 mass% Mg₂Si alloy composite material has been investigated by transmission electron microscopy (TEM) in order to determine the crystallographic orientation relationship. A thin sample of the Al₂O₃/Al-Mg-Si alloy composite material was obtained by the FIB method, and the orientation relationship between Al₂O₃ and MgAl₂O₄, which was formed on the surface of Al₂O₃ particles, was discovered by the TEM technique as follows: equation presented At the interface between the Al₂O₃ and the matrix the MgAl₂O₄ (spinel) crystals had facets of {111} planes. Spinels were not grown as thin films, but as particles consisting of {111} planes. They grow towards both the matrix and the Al₂O₃ particles.