Microstructure and properties of aluminum matrix composites fabricated by in-situ reaction between multi-oxide and aluminum

Al2O3 particles reinforced ZL109 aluminum matrix composites were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD), transmission electron microscopy (TEM) and tensile strength test. The results indicate that small size (about 0.1 μm) Al2O3 particles formed by in-situ reaction between multi-oxide and aluminum distribute uniformly in the matrix, and the orientation relation between Al2O3 and matrix is (001)α(Al)// (010)α-Al2O3 and [110]α(Al)// [001]α-Al2O3. After T6 heat treatment, the intermetallic compounds accompany with in-situ reaction uniformly disperse in the matrix and exist in the form of Al5FeSi, FeCr, Mg2Si, Al3Ni, Al2Cu and Al7Cu4Ni phase. Composite tensile strength can reach 163.4 MPa, improves by 7.9% than that of the matrix. With the increase of Al2O3 particles, the fracture mechanism of the composites at 25°C changes from ductile fracture to cleavage fracture, and then to transgranular fracture, while at 300°C, the brittle fracture changes to ductile fracture.