新型γ-TiAl基合金的高温氧化行为研究  

Elevated Temperature Oxidation Behavior of the New γ-TiAl Alloy

作　　者：罗媛媛[1,2] 奚正平[1] 卢亚锋[2] 毛小南[2] 杨义[2] 曾卫东[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 [2]西北有色金属研究院,陕西西安710016

出　　处：《稀有金属材料与工程》2014年第1期219-223,共5页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51001088)

摘　　要：研究了新型γ-TiAl基TiAl-3Ta-X(Cr,W)高温合金在800～900℃范围内的氧化行为。氧化增重实验及XRD,SEM分析结果表明,TiAl-3Ta-X(Cr,W)合金在800～900℃范围内氧化0～200 h条件下,由Wagner的氧化经验公式计算得氧化指数n在0.976～3.849之间,氧化激活能为203 kJ/mol,氧化符合线性-抛物线混合规律。试样表面形成氧化层,随着氧化温度的升高和时间的延长,氧化层厚度增加。经长时间氧化后,氧化产物由TiO2,Al2O3和AlTaO4组成,Ta的中间化合物中Ta-O键的存在能有效防止合金进一步氧化。The oxidation behavior of TiA-3Ta-X（Cr, W） alloy was investigated by thermogravimetric method. Isothermal experiments were carried out from 800 ℃ to 900 ℃ in air. The alloy microstructure and the composition as well as the composition distribution of the oxide scale were analysed by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. The results show that the oxidation kinetics obey linearity-parabolic law and the total activation energy is 203 kJ/mol at temperature range of 800-900 ℃ for 0-200 h. The scale thickness increases with the increase of time and temperature. A mixture oxide of protective A1203, A1TaO4 and TiO2 is formed for long time which becomes an important factor increasing the thermal stability of TiA1-3Ta-X （Cr, W）.

关 键 词：TiAl高温合金 氧化 氧化层 

分 类 号：TG132.33[一般工业技术—材料科学与工程]