Oxidation and peel-off mechanisms of oxide layer of the highly stabilized /3 type burn resistant alloy ti40

The alloy Ti40 is a highly stabilized type burn resistant titanium alloy. The oxidation and peel-off mechanisms of oxide layer of this alloy have been studied. The experimental results indicate that weight gain increases greatly with increasing temperature, however, the weight gain decreases for oxidizing at 1 050'C. The main products oxidized at 600'C are TiO₂ and V2O5. If oxidizing temperature is higher than 700'C > TiO₂ is the main products because of the vaporization of V2O5. With increasing temperature and time, the grains of oxide become coarse, the oxide film is porous, and the coherence force between oxide scale and . matrix decreases. The oxide scale cracks and peels if temperature is not less than 900'C. There are SiO compound in porous oxide scale if temperature is not less than 800'C. The amount of SiO increases with increasing temperature. The SiO compound changes from ball to star state, and vanishes after peel of oxide scale at 1 05C. There are non-continuous Cr2O3 product at the interface between oxide scale and matrix. The reason is that the alloy Ti40 does not possess good oxidation resistance. The oxidation mechanism is also analyzed, and a oxidation model is proposed. The mechanisms of crack and peel of oxide scale are discussed in detail.