(北京航空航天大学 材料科学与工程学院，北京 100191)
摘 要: 采用添加稀土元素Er改善Ti-16Al-27Nb合金的力学性能，分析其对合金组织结构和性能的影响。结果表明：添加微量Er可以细化合金的晶粒，但不改变合金基体的相组成，合金均由B2、a2和O相组成；当Er含量较低时，主要以固溶形式存在于合金中；当Er含量约为0.6%(摩尔分数)时，合金中将析出面心立方结构的富Er相，并弥散分布于基体中，随着Er含量的增加，富Er相尺寸变大且沿晶界聚集，导致合金性能下降。固溶强化和弥散强化是微量Er元素改善合金性能的原因，当添加0.6% Er时，合金具有优良的塑性变形能力。
关键字: Ti-Al-Nb合金；Er；显微组织；力学性能
（School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China）
Abstract:Rare earth element Er was added into Ti-16Al-27Nb alloy to improve the mechanical properties of the alloy. The effects of Er on the microstructure and properties of Ti-16Al-27Nb alloy were investigated. The results show that the grain size of the alloy can be refined by the trace addition of Er, but the main phase constituent of the alloy cannot be changed, i.e., the alloy basically consists of B2, a2 and O phases. When the content of Er additive is very low, Er will solute in the alloy while the content of Er additive is about 0.6% (mole fraction), fine Er-riched particles with face-centered cubic structure will precipitate homogeneously in the matrix. With the increase of the content of Er additive, the Er-riched phase will grow up obviously and segregate along the grain boundaries, which deteriorates the mechanical properties of the alloy. Based on the experimental results, conclusion can be drawn that solid solution strengthening and dispersion strengthening are the main mechanisms for Er element to improve the mechanical properties of the alloy. The alloy with 0.6% Er (mole fraction) shows excellent plastic deformation ability.
Key words: Ti-Al-Nb alloy; Er; microstructure; mechanical properties
