高能球磨与射频等离子体球化制备TiAl合金球形微粉

Fabrication of Micro-fine Spherical TiAl Alloy Powder by High-Energy Ball Milling and Radio Frequency Plasma Spheroidization

摘要:

以雾化法制备的大粒度TiAl预合金粉末为原料，采用高能球磨与射频等离子体球化工艺制备出TiAl合金微细球形粉末，并研究了其粉末特性。结果表明，采用上述工艺制备的TiAl合金粉末球形率高；粒度可控，数均粒径可控制在10~60 μm范围内；粉末粒径分布窄，粒度分布均匀度指数约为0.63。粉末氧含量随粒度降低而逐渐增加，数均粒径为31.5 μm的合金粉末的氧含量约为2.44‰；数均粒径为15.6 μm的合金粉末的氧含量约为3.51‰。制备的球形TiAl合金粉末主要由α2相及少量的γ相组成；粉末颗粒间成分均匀性良好，颗粒内部为均匀等轴晶组织，随着粉末粒度减小，晶粒组织趋于细化

关键词:TiAl合金;球形粉末;高能球磨;射频等离子体球化;粉末特性

Abstract:

Micro-fine spherical TiAl alloy powder was prepared by high-energy ball milling and subsequent radio frequency plasma spheroidization from atomized TiAl alloy powder with big particle size. The fabrication process and powder characteristics were investigated. The results show that the obtained powder exhibits good sphericity. The number-average particle size of the powder can be accurately controlled in the range of 10~60 μm, and the powder presents a narrow size distribution with a uniformity level of about 0.63. The powder oxygen content acts as a decreasing function of the particle size, which increases from 2.44‰ to 3.51‰ when the number-average particle size decreases from 31.5 μm to 15.6 μm. The spherical TiAl alloy power is composed of α2-Ti3Al and a small amount of γ-TiAl. The powder possesses homogeneous chemical composition and uniform equiaxed grain microstructure, and the grain size tends to be refined with the decrease of the particle size

Key words:TiAl alloy; spherical powder; high-energy ball milling; radio frequency plasma spheroidization; powder characteristics