稀土Y对Nb-Ti-Si基超高温合金组织及抗氧化性能的影响  

Effect of Y addition on microstructure and oxidation-resistant performance of Nb-Ti-Si based ultrahigh-temperature alloys

作　　者：张昊[1] 郭喜平[1] 乔彦强[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《材料热处理学报》2016年第1期81-86,共6页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51371145;51431003;U1435201)

摘　　要：采用真空非自耗电弧熔炼法制备了5种成分为Nb-22Ti-15Si-5Cr-3Al-3Hf-x Y(x=0,0.03,0.06,0.12,0.30 at%)的合金,并在1250℃下分别进行了1、10、20和50 h的高温氧化实验,研究Y含量对合金电弧熔炼态组织及其高温抗氧化性能的影响。结果表明:添加Y不改变电弧熔炼态合金相组成,组织仍由Nbss及γ-(Nb,X)5Si3相组成,但细化了共晶组织。高温氧化实验结果表明,不同Y含量合金在氧化不同时间后,氧化膜均由Nb2O5,Ti O2,Ti2Nb10O29和Ti Nb2O7组成;随着Y含量的增加,氧化膜中的孔洞和裂纹减少,合金单位面积氧化增重也逐渐减小,表明Y的添加能够显著提高合金的高温抗氧化性能。Nb-22Ti-15Si-5Cr-3Al-3Hf-x Y（ x = 0,0. 03,0. 06,0. 12,0. 30 at%） alloy ingots were prepared by vacuum non-consumable arc melting,and then the alloys were oxidized at 1250 ℃ for 1,10,20 and 50 h,respectively. The effects of Y content on microstructure and oxidation behavior of the alloys had been studied. The results show that the addition of Y has less influence on the phase constituents of the alloy. The microstructure of the alloys is composed of Nbss and γ-（ Nb,X）5Si3phases. However,the eutectic microstructure is refined significantly due to the Y addition. The oxidation tests show that the scales of the alloys with different Y contents have similar phase constituents,mainly consisting of Nb2O5,Ti O2,Ti2Nb10O29 and Ti Nb2O7. However,micro-holes and cracks in the scale as well as the mass gains per unit area of the alloy decrease with increasing Y contents in the alloys,indicating beneficial effects of Y additioin on the oxidation resistance of the alloy.

关 键 词：Nb-Ti-Si基超高温合金 Y含量 微观组织 抗氧化性能 

分 类 号：TG146.4[一般工业技术—材料科学与工程]