Oxidation of in situ synthesized TiC particle-reinforced titanium matrix composites

Abstract

The oxidation behavior of TiC particle reinforced titanium matrix composites (TMCs) was studied in a temperature range 550–650 °C in atmosphere. The in situ oxidation observation at the very initial stage was investigated by high-temperature optical microscopy in air. The oxide layer of long-term oxidation behavior was examined by scanning electron microscopy (SEM) combined with an energy dispersive X-ray spectroscopy unit (EDX), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The oxidation kinetics follows a parabolic rate law. The oxidation rate decreases gradually as the oxidation proceeds. The oxidation of the composite took place firstly on Ti because of the higher reactivity of Ti and O 2 than that of TiC and O 2. However, the TiC reinforcement can decrease the overall oxidation rate at 550, 600, and 650 °C. It is attributed to the formation of thin and dense oxidation, the enough strong interface cohesion between reinforcements and the titanium matrix alloy.