HRTEM Study of Interface Structure in Al2O3/2024Al Composite

The microstructures at the interfaces of Al2O3/2024Al composite manufactured by extrusion casting were investigated by transmission electron microscopy (TEM). The results indicate that no resultant production is found along the interfaces, and several coherent or semi-coherent interface relationship, such as Al(111)//Al2O3 ((11) over bar2 (1) over bar) Al(111)//Al2O3((21) over bar1 (1) over bar), Al(111)//Al2O3(11 (2) over bar0), are characterized along the explored interfaces of the composite. An edge dislocation is also found along one of the interfaces. It could be deduced that the Al matrix could nucleate and grow basing the nearby strengthening particle only when there is no obvious difference between value of the interplanar spacing of the matrix and the strengthening particle, and the strengthening particles can act as sites for heterogeneous nucleation of Al matrix. At same time, the reason for forming such interface features was analyzed from the viewpoint of crystallography.