中文摘要：

采用真空非自耗电弧熔炼方法制备了Nb-16Si—xFe原位复合材料（x=2，4，6，原子分数（％），分别简称为2Fe、4Fe、6Fe合金），研究了Fe含量对Nb-16Si合金的显微组织与室温力学性能的影响。结果表明：铸态及热处理态（1350℃真空退火100h）2Fe和4Fe合金主要由Nb基固溶体（Nbss）、Nb3Si和Nb4FeSi三相组成，随着Fe含量的增多，Nb3Si含量减少，而Nb4FeSi含量增加，6Fe合金仅由Nbss和Nb4FeSi两相组成；热处理后Nbss上有细小的硅化物析出；Nb-16Si合金中加入Fe元素后所生成的新相Nb4FeSi是一个硬脆的硅化物相，其显微硬度和室温断裂韧性分别为HV1110和1．22MPa·ml1/2；随着Fe含量由2％提高到6％，热处理态Nb-16Si—xFe合金的室温断裂韧性呈略微下降趋势，而硬度和压缩强度呈上升趋势。

英文摘要：

Nb-16Si- xFe in-situ composites （x = 2, 4, 6, atom fraction（%）, referred to 2Fe, 4Fe and 6Fe alloy, respectively, hereafter） were prepared by vacuum non-consumable arc-melting method and the effect of Fe additions on the microstructures and room-temperfiture mechanical properties of the Nb - 16Si alloy was studied. The results reveal that the as-cast and heat-treated （vacuum annealing 100 h at 1350 ℃） 2Fe and 4Fe alloys are composed of Nb solid solution （Nbss）, silicides of Nb3 Si and Nb4 FeSi, while the 6Fe alloy is composed of the Nbss phase and the Nb4FeSi silicide. As the Fe content increasing, the volume fraction of the Nb3Si phase decreases, while that of the Nb4 FeSi phase increases. Small silicde particles precipitate in the heat-treated Nbss phase. For the Nb4FeSi, a new stiffening phase in the Nb- 16Si alloy, its microhardness and fracture toughness are HV 1110 and 1.22 MPa m1/2 , respectively. With the increasing of the atom fration of Fe from 2% to 6%, the room-temperature fracture toughness of the heat treated alloys shows a decreasing tendency, while the hardness and compressive strength increase.