(北京航空航天大學 材料科學與工程學院，北京 100191)
摘 要: 采用添加稀土元素Er改善Ti-16Al-27Nb合金的力學性能，分析其對合金組織結構和性能的影響。結果表明：添加微量Er可以細化合金的晶粒，但不改變合金基體的相組成，合金均由B2、a2和O相組成；當Er含量較低時，主要以固溶形式存在于合金中；當Er含量約為0.6%(摩爾分數(shù))時，合金中將析出面心立方結構的富Er相，并彌散分布于基體中，隨著Er含量的增加，富Er相尺寸變大且沿晶界聚集，導致合金性能下降。固溶強化和彌散強化是微量Er元素改善合金性能的原因，當添加0.6% Er時，合金具有優(yōu)良的塑性變形能力。
關鍵字: Ti-Al-Nb合金；Er；顯微組織；力學性能
（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
