【摘要】 研究了金属间化合物-γTiAl基合金:Ti-48Al-2Cr-2Nb在1 123 K燃气环境中的高温氧化特征.检测了该合金在上述氧化条件下循环氧化总计1 080 ks(300 h,15次循环)的氧化增重情况,并对其氧化层的组成和结构用X射线衍射仪(XRD)和扫描电子显微镜(SEM)进行了分析和观测.研究发现:Ti-48Al-2Cr-2Nb在1 123 K燃气环境中具有优异的抗氧化能力,经历1 080 ks循环氧化后试样的氧化增重小于0.01 kg.m-2,而且其氧化动力学曲线近似符合抛物线氧化增重规律.对其氧化层结构的分析和检测表明:氧化层完整致密,无剥落现象发生.研究认为,Ti-48Al-2Cr-2Nb在1 123 K燃气环境中所表现的较强抗氧化能力主要是合金元素Cr和Nb的添加以及外在氧化条件的影响.其中大量合金元素的存在有效地促进了保护性Al2O3氧化层的形成,有利于氧影响层的稳定存在,并阻止了该合金内氧化的发生.更多还原

【Abstract】 The oxidation characters of a γ-TiAl based alloy: Ti-48Al-2Cr-2Nb in the simulated combustion gas at（1（）123 K） are investigated.The total mass gain of the alloy after cyclic oxidation for（1（）080） ks is measured.The phase composition and microstructure of the oxide scale are analyzed and observed by XRD and SEM.The study indicates that Ti-48Al-2Cr-2Nb alloy shows strong anti-cyclic oxidation resistance at（1（）123） K in the simulated combustion gas,and the total mass gain is less than 1×10^-2 kg·m^-2 after exposure in above oxidation condition for 1（）080 ks.The oxidation kinetics of the alloy nearly follows the parabolic oxidation law.Its oxide scale is compact and complete,and no spallation can be observed.The strong oxidation resistance of Ti-48Al-2Cr-2Nb in the simulated combustion gas at 1（）123 K is attributable to the alloying addition of Cr and Nb together with the external oxidation conditions,which are beneficial to the preferential formation of a protective Al₂O₃ layer in the oxide scale and the stabilization of oxygen influenced zone.更多还原