合金元素复合化对Ti_(2)AlNb合金高温抗氧化性能影响EI北大核心CSCD

Ti_(2)AlNb合金具有良好的工艺性能、综合力学性能和较低的密度等性能优势,是新型航空发动机的重要选材之一。为拓宽Ti_(2)AlNb合金的应用范围,需对传统Ti_(2)AlNb合金进行合金成分优化和工艺组织调控以进一步增强其高温抗氧化性能。本研究在传统Ti-Al-Nb三元合金体系基础上,综合设计Mo,Zr,W等合金复合化的方法提高Ti_(2)AlNb合金的抗氧化能力,通过对新型Ti_(2)AlNb合金在750℃和850℃的氧化增重行为分析、氧化层特征结构分析、表面氧化物种类和合金成分过渡分布分析等,发现Mo合金元素引起Ti_(2)AlNb合金在750℃上升至850℃时抗氧化性能的明显下降,Zr合金元素则始终保持着Ti_(2)AlNb合金良好的高温抗氧化能力;更为深入的截面试样SEM表征可将氧化层结构细分为氧化物层、富氧扩散层和组织演变层,Zr和W合金元素对850℃高温氧化过程中不同氧化层结构具有协同抑制作用,因此提出通过Zr和W合金元素复合的方法作为新型Ti_(2)AlNb合金抗氧化合金成分优化方向。

Effect of compound alloying on high temperature oxidation resistance property of Ti2AlNb alloy

As one of the important materials for new generation aeroengines,Ti₂AlNb alloy has many good properties,including good processability,great comprehensive mechanical properties and low density.In order to widen the application field of Ti₂AlNb alloy,the optimization of alloy composition and the control of process and microstructure need to be carried out to further enhance the oxidation resistance property of traditional Ti₂AlNb alloy.In this study,the compound method of Mo,Zr,W alloys on traditional Ti-Al-Nb alloy was designed to improve the oxidation resistance property of Ti₂AlNb alloy.The oxidation mass gain behaviour,the oxide layer structure,surface oxides and the alloy composition distribution of these Ti₂AlNb alloys during the high temperature oxidation process at 750℃and 850℃were analyzed and compared.It is found that the oxidation resistance of Ti₂AlNb alloy with Mo alloying element decreases obviously when temperature increases from 750℃to 850℃,while the oxidation resistance of Ti₂AlNb alloy with Zr alloying element still keeps excellent;the oxide scale microstructure of these Ti₂AlNb alloys is made up of oxidation layer,oxygen enrich layer and interstital affected layer according to the SEM morphology analysis of these cross-sections samples.It is believed that Zr and W alloying elements have the coordination repression effects on the formation of different oxide layers during the oxidation process at 850℃.Therefore,the kind of Ti₂AlNb alloy with both Zr and W alloying elements was recommended as the promising anti-oxidation Ti₂AlNb alloy.