(1. 南京航空航天大學(xué) 機(jī)電工程學(xué)院，南京 210016；2. 南昌航空大學(xué) 材料科學(xué)與工程學(xué)院，南昌 330063)
摘 要: 采用機(jī)械合金化與熱壓工藝制備以Nb固溶體為軟第二相的Laves相Nb/NbCr2復(fù)合材料。研究不同成分的Nb、Cr元素粉經(jīng)20 h球磨后在1 250 ℃，0.5 h熱壓工藝下所獲得的Nb/NbCr2復(fù)合材料的組織和性能。結(jié)果表明：隨著偏離Laves相化學(xué)配比的Nb含量的增大，材料的致密度、抗壓強(qiáng)度、塑性應(yīng)變均增加，而維氏硬度減小。Laves相含量為29%的Cr-77.5Nb合金的組織均勻，Nb固溶體與Laves相間隔分布，晶粒尺寸達(dá)到亞微米級(jí)，屈服強(qiáng)度為2 790 MPa，抗壓強(qiáng)度為3 174 MPa，塑性應(yīng)變達(dá)到5.44%，充分實(shí)現(xiàn)了細(xì)晶和軟第二相綜合增韌的效果。
關(guān)鍵字: Nb/NbCr2復(fù)合材料；機(jī)械合金化；熱壓；Laves相；顯微組織；力學(xué)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
