Effect of pre-oxidation of TiNi fibers on the interfacial and mechanical property of TiNif/Al composite

20 vol% TiNif/Al composite was fabricated by a pressure infiltration process. The effects of pre-oxidation of TiNi fibers on the interfacial and mechanical property of the composite were studied. As to avert severe interfacial reaction between the TiNi fiber and Al matrix, a dense oxide layer was formed on the surface of the TiNi fiber after it was oxidized in air for different time durations. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were used to study the interface of the composite. It was found that the TiO2 phase was the main component of the oxide layer. With increase in oxidation time, the thickness of the interfacial layers between TiNi fiber and Al matrix increased, and the tensile strength and elongation of the composite decreased. When the oxidation time was 1 h, the tensile strength of the composite was very close to the theoretical value of 272 MPa. Moreover, the interfacial layer can be divided into three parts: Ti-O layer next to the Al matrix, thin middle layer containing Ti element and the Ti-Ni layer next to the TiNi fiber.