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使用元素W、B、Y对Ti-45Al-8Nb合金进行了微合金化,研究了微合金化后高铌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,经过0.2B与0.1Y联合微合金化后合金的氧化增重小,氧化膜与基体的粘附性强,抗氧化性明显改善;经过0.2W与0.1Y微合金化后合金氧化增重明显,氧化膜容易脱落,合金抗氧化性下降;经过0.2B、0.2W、0.1Y联合微合金化后合金抗氧化性没有明显变化。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,联合添加B、Y促进了合金中的连续致密的Al2O3条带的形成,W、Y联合微合金化的合金中靠近基体处未形成连续的Al2O3条带,并且混合层中形成了较厚的低铌含量的TiO2层。W、B、Y联合微合金促进了混合层中富Al2O3层的形成。
The microalloying of Ti-45Al-8Nb alloy with the elements W, B, Y was carried out. The intermittent oxidation behavior of the high niobium TiAl-based alloy in still air at 900 ℃ after microalloying was studied. The results show that, compared with the Ti-45Al-8Nb alloy, the oxidation weight gain of the alloy after 0.2B and 0.1Y joint micro-alloying is small, the adhesion of the oxide film to the matrix is strong and the oxidation resistance is obviously improved; Compared with 0.1Y, the oxidation resistance of the alloy is obviously increased, the oxide film is easy to fall off and the oxidation resistance of the alloy is decreased. After 0.2B, 0.2W, 0.1Y combined with micro-alloying, the oxidation resistance of the alloy has no obvious change. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis of the oxide films showed that the addition of B and Y promoted the formation of continuous and dense Al2O3 bands in the alloy. The combination of W and Y In the micro-alloying alloy, no continuous Al2O3 band was formed close to the matrix, and a thick TiO2 layer with a low niobium content was formed in the mixed layer. W, B, Y combined micro-alloying promoted the formation of Al 2 O 3 -rich layers in mixed layers.