超细晶Laves相NbCr2颗粒增强Nb基复合材料的制备及其组织性能研究  

Preparation and Investigation on Microstructure and Properties of Ultra-fine Grained Laves Phase NbCr_2 Particulate Reinforced Nb Matrix Composites

作　　者：肖璇[1] 鲁世强[1] 胡平[1] 黄铭刚[1] 李鑫[1] 

机构地区：[1]南昌航空大学材料学院

出　　处：《航空材料学报》2008年第3期44-48,共5页Journal of Aeronautical Materials

基　　金：国家自然科学基金(50474009);航空科学基金(05G56003);江西省自然科学基金(0350045)

摘　　要：采用机械合金化+热压工艺制备了Laves相NbCr2增强的Nb基复合材料。研究了Nb-22.5Cr配比成分的Nb,Cr元素粉经MA30h后在1250℃分别热压10min,20min和30min所获得的Nb/NbCr2复合材料的组织和性能。结果表明:三种热压时间均可制备出组织均匀,致密度高的Nb/NbCr2复合材料,体积分数约为30%的近等轴状的Laves相NbCr2颗粒弥散分布于Nb固溶体基体中。热压20min的试样具有最佳的组织和性能,其Laves相NbCr2的晶粒尺寸达到亚微米级,致密度达到99.2%,维氏硬度为9.41GPa,屈服强度为2950 MPa,抗压强度为3345 MPa,塑性应变达到了7.01%,充分实现了Laves相NbCr2颗粒强化和细晶强韧化的效果。Laves phase NbCr2 reinforced Nb matrix composites were prepared by mechanical alloying followed by hot pressing. Microstructure and properties were investigated on Nb/NbCr2 composites prepared from 30h mechanically alloyed powders of elemental chromium and niobium powders with the Nb： Cr = 77. 5： 22. 5 atom ratio by hot pressing at 1250℃ for lOmin,2Omin and 30min. The results indicate that Nb/NbCr2 composites with high relative density and homogeneous microstructure are obtained for three hot pressing time. The near equiaxed Laves phase NbCr2 granules with the volume fraction of 30% are distributed dispersedly in Nb solid solution matrix. The sample hot pressed for 20min has the optimum microstructure and properties, the grain sizes of Laves phase NbCr2 reach the submicron level, the sample has a relative density of 99.2% , Vickers hardness of 9.41GPa, yield strength of 2950MPa, compress strength of 3345MPa and strain of 7.01%. The effect of both Laves phase NbCr2 particulate reinforcement and fine grain strengthening and toughening has been fully realized.

关 键 词：机械合金化 热压 Laves相NbCr2 Nb基复合材料 组织与性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程]