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研究了航空钛合金损伤结构梯度改性修复层和Ti600基体在800℃下的氧化行为;采用恒温或循环氧化增重法、氧化速度常数、活度等理论计算研究了氧化的热力学和动力学规律;利用扫描电镜(SEM)和X射线衍射(XRD)等分析了氧化膜形貌和组成。结果表明:梯度修复层有较好的抗氧化性能,其循环氧化动力学曲线基本符合抛物线规律;Ti600基体属次抗氧化级,其循环氧化动力学曲线近似符合抛物线-直线规律;梯度修复层氧化膜由金红石结构的TiO2和少量Cr2O3组成,厚度5~6μm,与基体连接紧密,且致密、连续,为短纤维状组织;Ti600基体的氧化膜厚度达55μm左右,明显分为内氧化区、中致密层和外疏松多孔层,为多面体规则形状组织。
The oxidation behavior of Ti6Al modified Ti6Al matrix and the damaged Ti6Al6Al6O6 alloy substrate at 800 ℃ was studied. The thermodynamics and kinetics of oxidation were studied by the theory of constant temperature or cyclic oxidation, the rate constant of oxidation and activity. The morphology and composition of the oxide film were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the gradient-repaired layer has good oxidation resistance and the cyclic oxidation kinetics curve basically meets the parabolic law. The Ti600 matrix belongs to the secondary oxidation resistance stage, and its cyclic oxidation kinetic curve approximates the parabola-linear rule. The gradient- The film is composed of rutile TiO2 and a small amount of Cr2O3 with a thickness of 5 ~ 6μm, which is closely connected with the substrate and is dense and continuous with short fibrous structure. The thickness of oxide film of Ti600 substrate is about 55μm, which is obviously divided into inner oxidation zone The dense layer and loose porous layer, the regular shape of polyhedron organization.