摘要
研究了Ti60合金(Ti-5.6Al-4.8Sn-2.OZr-l.OMo-0.85Nd-0.34Si)在650～750℃下的高温氧化行为;采用恒温或循环氧化增重方法、氧化速度常数、活度等理论计算研究了合金氧化的热力学和动力学规律;用X射线衍射(XRD)、扫描电子显微镜(SEM)等方法,研究氧化膜的表面形貌和结构;采用俄歇电子能谱(AES)分析元素沿深度方向的分布,研究元素在氧化过程中的扩散行为。研究结果表明:Ti60合金在650℃和700℃有较好的抗氧化性能,其循环氧化动力学曲线基本上符合抛物线规律;在750℃,氧化严重,其循环氧化动力学曲线近似符合抛物线-直线规律。氧化层由金红石结构的TiO_2氧化物和少量的Al_2O_3组成。氧化表面形貌为网篮状组织,这是由于a相和β相的成分和结构不同,界面扩散和体扩散差异导致的氧化程度不同所造成的。稀土第二相处氧化严重,表面裂纹大多产生于稀土第二相颗粒。
The oxidation of Ti60 alloy (Ti-5. 6A1-4. 8Sn-2. OZr-1. OMo-0. 85Nd-0. 34Si) has been investigated. Thermodynamic and dynamic laws were studied by means of calculating the oxidation weight gain, oxidation rate constants and activities. The microstructure and morphology of oxidation scales on surface were examined with XRD and SEM. The element profile along oxidation layer was studied by AES to understand the diffusion behavior. The results indicate that Ti60 alloy exhibited the parabolic rule of oxidation rate at 650℃ and 700℃ , but obeyed the parabolic-linear rule at 750℃, The oxidation scales are composed of TiO2 and A12O3. The morphology of oxidized surface possesses grill-like structure because α phase, β phase, and α/β interface are different in oxidation rate. Oxidation of rare earth phases is more serious than that of substrate.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2003年第6期18-22,共5页
Journal of Materials Engineering
基金
国家自然科学基金(59871003)
