中文摘要：

采用水冷铜坩埚感应熔炼制备了名义成分为Ti-45A l-8.5Nb-0.2W-0.2B-0.02Y（at%）的大尺寸铸锭,经机械破碎后,采用流化床气流磨和射频等离子体球化工艺制备出高铌TiA l合金粉末,并研究了其特性。结果表明,采用上述工艺可大量制备出球形度高、粒度可控的高铌TiA l合金粉末;粉末的氧含量随粒度的细化而逐渐增加;高铌TiA l合金球形粉末的相组成主要为α2相及少量的β相;球形合金粉的表面和内部组织与粒度密切相关,平均粒度为90μm的粗粉表面及内部均呈枝状,颗粒内部存在网状富A l偏析相,随着粉末粒度减小,球形合金粉末表面趋于光滑,内部偏析逐渐减弱。此外,平均粒度为90μm的粗粉各颗粒间成分均匀,随着粉末粒度细化,颗粒间成分均匀性降低。

英文摘要：

Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y（at%） ingot was prepared using a vacuum induction furnace,and then machined with a crusher in argon atmosphere.Subsequently,microfine spherical high Nb containing TiAl alloyed powders were obtained by fluidized bed jet milling in inert gas and then by radio frequency argon plasma.The fabrication process and characteristics of the powders were investigated.The results show that the powders fabricated by this process is highly refined and spheroidized,and the particle size is accurately controlled in a small interval.The plasma-spheroidized powders are dominated by α2-Ti3Al with a minor amount of β-Ti2AlNb.The oxygen content becomes higher gradually with the decrease of the particle size.The exterior and interior microstructures of the alloyed powders strongly depend on the particle size.The powders with an average particle size of 90μm show dendritic microstructure,and network Al-rich phase segregation exists within the particles.With the particle size decreasing,the surface of the powders tends to be smooth,and the internal segregation is gradually weakened.In addition,the 90μm powders possess high composition homogeneity,and with the decrease of the particle size the composition homogeneity declines gradually.