氧在 Ti-1100 高温钛合金氧化中的扩散规律

Diffusion Kinetics of Oxygen in Oxidation of Ti1100 High Temperature Titanium Alloy

测量了Ｔｉ１１００合金在６００～７５０℃氧化１００ｈ后氧化层的厚度和氧化层＼固溶体界面处的氧浓度以及基体富氧层的深度、显微硬度的变化．合金在该温度区间的氧化增重由氧化物的增长和富氧固溶体的形成两部分组成，它们均呈抛物线规律变化．利用扩散方程和氧化物＼固溶体界面处“有效氧浓度”计算出氧在氧化物中的扩散系数是氧在固溶体中的３～６倍．根据富氧层的深度所计算的氧在固溶体中的扩散激活能与扩散系数的线性回归结果具有相当好的一致性．

Oxide scale thickness and oxygen concentration at oxide/solid solution boundary are measured by SEM microscope and electron probe microscope,respectively, for the Ti1100 alloy oxidized at 600～750℃ range for 100h. The depth of surface oxygen enrichment ( S.O.E.) layer and microhardness profiles are tested. Diffusion coefficients for oxygen in TiO2 are calculated by using diffusion equation and 'effective oxygen concentration' at oxide/solid solution boundary, which are about 3～6 times the value in an alphaTi. The diffusion activation energy for oxygen in solid solution calculated by measuring the depth of S.O.E.layer is in excellent agreement with the result of linear regression value calculated by diffusion coefficients Ds.