Effect of ball milling time on microstructure and properties of Laves phase NbCr2 alloys synthesized

• 作 者: XIAO Xuan LU Shi-qiang HU Ping
• 机 构: School of Materials Science and Engineering,College of Electromechanical Engineering,Department of M
• 出 处: 中国有色金属学报（英文版）
• 发表日期: 2004年期
• 关键词: Laves phase NbCr2 mechanical alloying hot pressing microstructure mechanical pro

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.