中文摘要：

采用恒温氧化增重方法,在静态空气中研究了Ti2Al Nb基合金轧板在650,700,750和800℃保温100 h条件下的高温抗氧化性能。利用扫描电子显微镜（SEM）、能谱仪（EDS）和X射线衍射（XRD）技术分析了氧化表面、截面形貌、元素分布以及物相。Ti2Al Nb基合金轧板,在650℃下未见明显的氧化层、700℃时氧化层厚度极小、800℃时氧化层厚度急剧增加。研究结果表明,在温度低于700℃条件下,氧化增重小于1 mg·cm-2,属于完全抗氧化级别。在750℃条件下,氧化增重明显,出现氧化分层,达到抗氧化级别。随着温度的升高,在800℃时有明显的氧化分层现象,但未形成连续致密的氧化层,氧化层出现明显孔洞。氧化产物主要为棱柱状的Ti O2相、层片状的Al Nb O4相和针状相。温度越高,分层越明显,富氧层越厚,危害性氧化物越多,氧化加剧趋势越明显。

英文摘要：

High temperature oxidation resistance behavior of as-rolled Ti2 Al Nb-based alloy at 650,700,750 and 800 ℃ for up to100 h exposure was investigated by means of isothermal oxidation tests in static laboratory air. Oxide layer morphology of surface and cross section,phase determination and element distribution of the as-rolled Ti2 Al Nb-based alloy,were evaluated using X-ray diffraction（ XRD）,scanning electron microscope（ SEM） and energy dispersive spectroscopy（ EDS） technology. Oxidation layer was hardly found at 650 ℃. Extremely thin oxidation layer was found at 700 ℃,while the thickness of oxidation layer increased significantly at800 ℃. The results showed that the mass gain was significantly lower than 1 mg·cm- 2,especially for exposures below 700 ℃,meeting the level of fully oxidation resistance. The mass grain increased and oxidation stratification was observed at 750 ℃,meeting the level of oxidation resistance. With the temperature increasing,the oxide layers delaminated obviously,but continuous oxidation films didn＇ t form and obvious pores appeared in the oxidation films at 800 ℃. There were three kinds of oxides,including prismatic Ti O2 phase,lamellar Al Nb O4 phase and acicular phases. The higher the oxidation temperature was,the thicker the layers were,and the more harmful oxidation products formed.