全片层组织TiAl–Nb合金的高温氧化行为及氧化层结构表征  

Oxidation Behavior and Oxide Scale Characteristics of TiAl-Nb Alloy with Full Lamellar Microstructure at High Temperature

作　　者：刘杰[1] 薛祥义[1] 杨劼人[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《稀有金属材料与工程》2015年第8期1942-1947,共6页Rare Metal Materials and Engineering

基　　金：国家重点基础研究发展计划资助(2011CB605503)

摘　　要：以Ti-42Al-8Nb-0.2W-0.1Y(at%)合金为研究对象,通过热处理获得全片层组织,片层团尺寸约为85μm,在900℃空气条件下,对合金进行了100 h的抗氧化实验,主要研究了该Ti Al-Nb合金的高温抗氧化行为,并对氧化层的结构、成分及形成过程进行了深入分析。利用OM、SEM、XPS、XRD、和EDS对试样的微观结构、相组成及微区成分进行表征。结果表明:在900℃空气条件下,具有全片层组织的Ti Al-Nb合金,其恒温氧化动力学曲线符合近抛物线规律;长时氧化后,合金表面生成了结晶状颗粒氧化物,为Ti O2和A12O3的混合物;氧化层主要由外表面氧化层、中间过渡层和基体层构成,氧化膜完整厚度大约为6μm。由此可知,添加了合金元素且具有小尺寸片层团组织的Ti Al合金在900℃高温时,具有较好的抗氧化性能。The oxidation behavior of Ti-42Al-8Nb-0.2W-0.1Y alloy with lamellar structures achieved by heat treatment was investigated by a thermogravimetric method at 900 °C for 100 h in air. Size of the full lamellar colony in the Ti Al-Nb alloy is 85 μm, and the alloy＇s microstructure was observed by optical microscope（OM） and scanning electron microscopy（SEM）. The composition as well as the composition distribution of the oxide scale was analyzed by energy dispersive spectroscopy（EDS）, X-ray diffractometry（XRD） and X-ray photoelectron spectroscopy（XPS）. Results show that oxidation kinetic curves of the Ti Al-Nb alloy accord with the parabolic curve law. Crystalline oxide particles composed of Ti O2 and A12O3 cover the alloy surface after long time oxidation; the structure of oxide scale involves three layers, outside oxide scale, intermediate layer and the substrate. In conclusion, Ti-42Al-8Nb-0.2W-0.1Y alloys with small size lamellar colony structure have a good oxidation resistance at 900 °C in air.

关 键 词：TIAL合金 显微组织 片层结构 氧化行为 

分 类 号：TG146.23[一般工业技术—材料科学与工程]