(1. 南京航空航天大学 机电工程学院，南京 210016；2. 南昌航空大学 材料科学与工程学院，南昌 330063)
摘 要: 采用机械合金化与热压工艺制备以Nb固溶体为软第二相的Laves相Nb/NbCr2复合材料。研究不同成分的Nb、Cr元素粉经20 h球磨后在1 250 ℃，0.5 h热压工艺下所获得的Nb/NbCr2复合材料的组织和性能。结果表明：随着偏离Laves相化学配比的Nb含量的增大，材料的致密度、抗压强度、塑性应变均增加，而维氏硬度减小。Laves相含量为29%的Cr-77.5Nb合金的组织均匀，Nb固溶体与Laves相间隔分布，晶粒尺寸达到亚微米级，屈服强度为2 790 MPa，抗压强度为3 174 MPa，塑性应变达到5.44%，充分实现了细晶和软第二相综合增韧的效果。
关键字: Nb/NbCr2复合材料；机械合金化；热压；Laves相；显微组织；力学性能
（1. College of Electromechanical Engineering, Nanjing University of Aeronautical and Astronautics, Nanjing 210016, China 2. Department of Material Science and Engineering, Nanchang Hangkong University,Nanchang 330063, China）
Abstract:Abstract: The Nb/NbCr2 composite materials with the soft second phase were prepared by mechanical alloying and hot pressing. The microstructure and mechanical properties were investigated on the Nb/NbCr2 composite materials prepared from 20 h mechanically alloyed powders of elemental chromium and niobium powders by hot pressing at 1 250 ℃ for 0.5 h. The results indicate that with increasing Nb content of off-stoichiometry Laves phase, the alloys have higher relative density, compressive strength and strain, but have smaller Vickers hardness. The Cr-77.5Nb alloy with homogeneous microstructure and sub-micron-sized grains is obtained by hot pressing at 1 250 ℃ for 0.5 h. Furthermore, the alloy with the content of 29% Laves phase has a yield strength of 2 790 MPa, compressive strength 3 174 MPa and strain 5.44%. The effect of fine grain toughening and soft second phase toughening is fully realized.
Key words: Nb/NbCr2 composite; mechanical alloying; hot pressing; Laves phase; microstructure; mechanical properties
