机械合金化-热压制备Nb/NbCr_2复合材料的组织与性能  

Microstructure and properties of Nb/NbCr_2 composites prepared by mechanical alloying followed by hot pressing

作　　者：肖璇[1] 鲁世强[2] 马燕青[2] 胡平[2] 黄铭刚[2] 聂小武[2] 

机构地区：[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

出　　处：《中国有色金属学报》2007年第11期1761-1766,共6页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(50474009);航空科学基金资助项目(05G56003);江西省自然科学基金资助项目(0350045);江西省材料科学与工程研究中心基金资助项目(ZX200401001)

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。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.

关 键 词：Nb/NbCr2复合材料 机械合金化 热压 LAVES相 显微组织 力学性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程] TG146.4[金属学及工艺—合金]