微量Y和Hf对高铌TiAl基合金高温抗氧化性的影响

Influence of Trace Y and Hf on the High-Temperature Oxidation Resistance of TiAl Based Alloys with High Nb Content

摘要:

使用元素Hf和Y对Ti-45Al-8Nb合金进行了微合金化，研究了微合金化前后高铌TiAl基合金在900 ℃静止空气中的断续氧化行为。结果表明，与Ti-45Al-8Nb合金相比，0.5Hf (mol%)微合金化后合金的抗氧化性无明显变化，0.1Y (mol%)微合金化后合金抗氧化性增强，0.5Hf与0.1Y联合微合金化后合金氧化膜与基体粘附性明显增强，但合金氧化增重明显。对氧化膜进行的扫描电镜(SEM)、能谱分析(EDS)及X射线衍射（XRD）分析表明，单独添加Y及Hf、Y联合添加促进了合金中形成以Al2O3为主的连续致密的氧化层，Hf、Y联合微合金化的合金中存在局部内氧化现象降低了该合金的抗氧化性

Abstract:

The interrupted oxidation behavior of Hf and Y micro-alloyed TiAl-based alloys with high Nb content at 900 oC in static air was investigated. The results show that the addition of 0.5%Hf (mol%, similarly hereinafter) has few effects on the oxidation resistance of the high-Nb alloy, the addition of 0.1%Y improves the oxidation resistance, while the combined addition of 0.1%Y and 0.5% Hf enhances the adherence of oxide scale but reduces the oxidation resistance. Oxidized samples were examined by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD). It is found that the addition of 0.1%Y and the combined addition of 0.5%Hf and 0.1%Y promote the formation of continuous and compact Al2O3 oxide scale. The combined addition of 0.5%Hf and 0.1%Y into the high-Nb alloy results in the partial internal oxidation of the alloy, impairing the oxidation resistance of TiAl