高能球磨与射频等离子体球化制备TiAl合金球形微粉.docVIP

  高能球磨与射频等离子体球化制备 TiAl 合金球形微粉# 路新，刘程程，朱郎平，何新波，曲选辉* 5 10 （北京科技大学新材料技术研究院，北京 100083） 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 TiAl 合金粉末球形度高；粒度可控，数均粒径可控制在 10~60μm 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，制备的数均粒径为 31.5 μm 的合金粉末的氧含量约为 2.4‰；数均粒径为 15.6μm 的合金粉末的氧含量约为 3.5‰。 制备球形 TiAl 合金粉末主要由α2 相及少量的γ相组成的；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 中图分类号：TG146.4 15 Fabrication of Micro-fine Spherical TiAl Alloys by High-energy Ball Milling and Radio Frequency Plasma Spheroidization LU Xin, LIU Chengcheng, ZHU Langping, HE Xinbo, QU Xuanhui 20 25 30 (Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083) Abstract: Micro-fine spherical TiAl alloy powder was prepared by high-energy ball milling and radio freqencny plasma spheroidization from atomized TiAl alloy powder with big particle size. The fabrication process and characteristics of the powder were investigated. The results show that the fabricated 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 has a narrow size distribution with a uniformity level of about 0.63. The powder oxygen content acts as a decreasing function of particle size, which increases from 2.4‰ to 3.5‰ when the number-average particle size decreases from 31.5 μm to 15.6 μm. The spherical TiAl power is composed of α2-Ti3Al and 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 particle size. Keywords: TiAl alloys; spherical powder; high-energy ball milling; radio frequency plasma spheroidization; powder characteristics 35 0 前言 TiAl 基合金具有比重低、高温强度好、抗氧化、抗蠕变性能优良等优势，被认为是最 有希望的新一代轻质高温合金，在航空航天、汽车、生物工程、环保等技术领域有十分广阔 的应用和发展前景[1-4]。但是，TiAl 合金普遍存在室温延性低、塑性加工成形困难、制备成 40 本高等问题，阻碍了其工业化实际应用。在众多