Nb颗粒增韧Ti-45Al-5Nb-0.3W合金的高温氧化行为  

High temperature oxidation behavior of Nb-particle reinforced Ti-45Al-5Nb-0.3W alloy

作　　者：黄佳妮 李慧中[1,2,3] 梁霄鹏[1,2,3] 车逸轩 HUANG Jiani;LI Huizhong;LIANG Xiaopeng;CHE Yixuan(School of Materials Science and Engineering,Central South University,Changsha 410083,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;Key Laboratory of Nonferrous Metal Materials Science and Engineering,Ministry of Education,Central South University,Changsha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学粉末冶金国家重点实验室,长沙410083 [3]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2023年第5期456-464,472,共10页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(52274402,52174381)。

摘　　要：通过热等静压制备2%Nb颗粒增韧Ti-45Al-5Nb-0.3W(摩尔分数)合金(Nb_(p)/TiAl合金),并于1280℃热处理24 h使元素扩散充分,富Nb区转变为层片组织与γ晶粒。在800、850和900℃空气中进行恒温氧化,利用光学显微镜、X射线衍射、扫描电镜、能谱仪和电子探针显微分析,研究合金氧化前后的物相组成和氧化膜的结构,揭示Nb_(p)/TiAl合金的氧化机理。结果表明:Nb_(p)/TiAl合金在800、850与900℃恒温氧化时的氧化动力学曲线均为抛物线型,在100 h氧化后单位面积的质量增量分别为3.32、7.36和17.27 g/m^(2);合金表面均形成了具有保护性的氧化膜,氧化膜为TiO_(2)/Al_(2)O_(3)/(Al_(2)O_(3)+TiO_(2)+NbO)/(TiN+Ti_(2)AlN+AlNb_(2))的多层结构,能有效抑制O元素在合金中的扩散,提高合金的抗氧化性能。Ti-45Al-5Nb-0.3W(mole fraction)alloy(Nb_(p)/TiAl alloy)toughened by 2%Nb particles was prepared by hot isostatic pressing.After heat treatment at 1280℃for 24 h,the elements diffused fully,and the Nb-rich region transformed into the lamellar structure andγgrains.The phase composition and oxide film structure of the alloy before and after oxidation were studied by optical microscope,X-ray diffraction,scanning electron microscope,energy spectrometer,and electron probe microanalysis,and the oxidation mechanism of Nb_(p)/TiAl alloy was revealed.The results show that the oxidation kinetics curves of Nb_(p)/TiAl alloy during isothermal oxidation at 800,850,and 900℃are parabolic,and the mass increments per unit area after 100 h oxidation are 3.32,7.36 and 17.27 g/m^(2),respectively.A protective oxide film is formed on the alloy surface with multi-layer structure of TiO_(2)/Al_(2)O_(3)/(Al_(2)O_(3)+TiO_(2)+NbO)/(TiN+Ti_(2)AlN+AlNb_(2)),which can effectively inhibit the diffusion of O element in the alloy and improve the oxidation resistance of TiAl alloy.

关 键 词：Nb颗粒 TIAL合金 粉末冶金 热处理 高温氧化 

分 类 号：TG146[一般工业技术—材料科学与工程]