Effect of ball milling time on microstructure and properties of Laves phase NbCr_2 alloys synthesized by hot pressing  

作　　者：肖璇 鲁世强 胡平 黄铭刚 M.W.FU 

机构地区：[1]School of Materials Science and Engineering, Nanchang Hangkong University [2]College of Electromechanical Engineering, Nanjing University of Aeronautical and Astronautics [3]Department of Mechanical Engineering, The Hong Kong Polytechnic University

出　　处：《中国有色金属学会会刊：英文版》2009年第3期545-551,共7页Transactions of Nonferrous Metals Society of China

基　　金：Project(50474009) supported by the National Natural Science Foundation of China;Project(05G56003) supported by the Aviation Science Foundation of China;Project(ZX200401001) supported by the Natural Science Foundation of Jiangxi Province,China

摘　　要：Laves phase NbCr2 alloys with a composition of Nb-66.7Cr (molar fraction, %) were prepared by mechanical alloying and hot pressing. The microstructures and properties of the Laves phase NbCr2 alloys, prepared from elemental niobium and chromium powders under various ball milling time by hot pressing at 1 250 ℃ for 0.5 h, were investigated. The results indicate that if the ball milling time is longer than 40 h, the synthesizing reaction of Laves phase NbCr2 can be accomplished much sufficiently. Then the nearly full-dense Laves phase NbCr2 alloys can be prepared by hot pressing from ball milled powders with more than 40 h. The hot pressing sample with homogeneous and fine microstructure made from 40 h ball milled powders has the optimum microstructure and properties. It has a relative density of 98.1%, Vickers hardness of 11.4 GPa, compress strength of 1 981 MPa and fracture toughness of 4.82 MPa·m1/2. The effect of fine grain toughening is fully realized.Laves phase NbCr2 alloys with a composition of Nb-66.7Cr （molar fraction, %） were prepared by mechanical alloying and hot pressing. The microstructures and properties of the Laves phase NbCr2 alloys, prepared from elemental niobium and chromium powders under various ball milling time by hot pressing at 1 250℃ for 0.5 h, were investigated. The results indicate that if the ball milling time is longer than 40 h, the synthesizing reaction of Laves phase NbCr2 can be accomplished much sufficiently. Then the nearly full-dense Laves phase NbCr2 alloys can be prepared by hot pressing from ball milled powders with more than 40 h. The hot pressing sample with homogeneous and fine microstructure made from 40 h ball milled powders has the optimum microstructure and properties. It has a relative density of 98.1%, Vickers hardness of 11.4 GPa, compress strength of 1 981 MPa and fracture toughness of 4.82 MPa·m^1/2. The effect of fine grain toughening is fully realized.

关 键 词：金合成热压 性能 铬元素 球磨粉末 

分 类 号：TG131[一般工业技术—材料科学与工程]