(1. 哈尔滨工业大学 材料科学与工程学院，哈尔滨 150001；
2. 哈尔滨工业大学 金属精密热加工国家级重点实验室，哈尔滨 150001；
3. 重庆长安汽车股份有限公司，重庆 404100)
摘 要: 通过钨极电弧熔炼制备不同Nb含量的高铌Ti-46Al-xNb (x=0, 6, 7, 8, 9，摩尔分数，%)合金，研究Nb含量对高铌TiAl基合金凝固组织和力学性能的影响规律。结果表明：不同Nb含量TiAl基合金的显微组织为近层片组织，同时，铸态组织存在枝晶间Al的偏析和层片内部Nb的网状偏析。X射线衍射分析表明，高铌TiAl基合金中存在γ相和α2相。室温压缩试验结果表明，几种高铌TiAl基合金中Ti-46Al-7Nb合金的综合力学性能较好，压缩断裂强度为1 715MPa，压缩率为24.21%。扫描电镜断口分析表明，不同Nb含量的Ti-46Al合金均以脆性断裂为主。
关键字: TiAl基合金；铌；显微组织；力学性能
（1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China;
3. Chongqing Changan Automobile Co., Ltd., Chongqing 404100, China）
Abstract:Nb containing Ti-46Al-xNb (x=0, 6, 7, 8, 9, mole fraction, %) alloys were prepared through tungsten arc-melting. The effect of Nb addition on the microstructures and mechanical properties were studied. The results show that a coarse fully lamellar (FL) microstructure is observed in the as-cast Ti-46Al-xNb alloys. At the same time, there are dendrite segregation of Al in the cast structure and the internal network segregation of Nb in the layer. XRD results indicate that Ti-46Al-xNb alloys are only composed of γ and α2 phases. The results of compression test at room temperature show that the Ti-46Al-7Nb alloys exhibit superior mechanical properties, with ultimate compressive strength of 1 715 MPa and compressibility of 24.21%. Scanning electron microscopy (SEM) observation indicates that the fracture mode of Ti-46Al-xNb alloys is mainly brittle fracture.
Key words: TiAl-based alloy; Nb; microstructure; mechanical property
