关键词: 高温抗氧化性, 拉伸试验, 钛合金, 氧化锆涂层

Abstract: Oxidation of the Ti6Al4V alloy at high temperature is a problem for the sound products. In order to protect the alloy from oxidation, surface coating method has been attempted and several coating materials has been investigated. A zircon coating is applied to the surface of Ti6Al4V alloy by plasma spray and the effect of coating on the superplasticity of the alloy as well as the oxidation behavior of the oxidation are studied. Uniaxial tensile tests are conducted at 800 ℃, 850 ℃ and 900 ℃ with an initial strain rate of 0.000 1 s–1, 0.00 1 s–1, 0.01 s–1 and 0.1 s–1. Studies show that an oxide film is formed on the surface of Ti6Al4V alloy and no such oxide film is found in the coated specimens. XRD and EDX analysis indicate that this oxide film mainly consists of TiO2. The thickness of the oxide film increases with increasing temperature and exposure time. Studies show that the elongations of the coated specimens are higher than those of the uncoated ones, while the ultimate strength and yield strength of the alloy are not changed. The difference in elongation between the coated and uncoated specimens is influenced by the temperature and initial strain rate. However, studies also show that there are some clefts formed on the coating layers at the later stage of deformation due to the brittle nature of the coating layers.

Key words: High temperature oxidation resistance, Tensile test, Titanium alloys, Zirconia coating