VIGA-CC法制备球形Ti-35.8Al-18.4Nb合金粉末及其性能研究

以真空自耗电弧熔炼的Ti-35.8Al-18.4Nb（质量分数）合金铸锭为原料，采用水冷铜坩埚真空感应熔炼气雾化制粉技术（water-cooled copper crucible vacuum induction melting-gas atomizing，VIGA-CC）制备球形Ti-35.8Al-18.4Nb合金粉末，利用振动筛分法、扫描电子显微镜（scanning electron microscope，SEM）观察、X射线衍射（X-ray diffraction，XRD）分析等手段对所制备的粉末进行性能表征。结果表明，VIGA-CC技术制备的粉末粒度分布较宽，主要分布在45~150 μm之间，呈正态分布，其中粒径不高于45 μm粉末收得率为15.8%，粒径不低于150 μm粉末收得率为12%；粉末流动性为27.2s·(50 g)-1]，粉末中氧质量分数的增量小于0.01×10-6，粉末整体氧质量分数小于0.06×10-6；TiAlNb合金粉末主要以γ（TiAl）相和α₂（Ti₃Al）相为主，随着粉末粒径的减小，冷却速率逐渐提高，γ（TiAl）相逐渐减少，α₂（Ti₃Al）相逐渐增加；大颗粒粉末表面为枝状冷凝组织，小颗粒粉末为光滑表面。

Preparation and properties of spherical Ti-35.8Al-18.4Nb alloy powders by VIGA-CC method

Spherical Ti-35.8Al-18.4Nb (mass fraction) alloy powders were prepared by the water-cooled copper crucible vacuum induction melting-gas atomizing (VIGA-CC) technology, using the TiAlNb alloy ingots prepared by vacuum consumable arc melting as the raw material. The properties of the TiAlNb alloy powders were characterized by vibration sieving, scanning electron microscope (SEM), and X-ray diffraction (XRD). In the results, the powder size distribution exhibits a normal state in the range of 45~150 μm. The powder yield with the particle size less than 45 μm is 15.8%, and that larger than 150 μm is 12%. The powder fluidity is 27.2 s·(50 g)-1]. The oxygen increment by mass in the powders is less than 0.01×10-6, and the total oxygen content by mass in the powders is less than 0.06×10-6. The TiAlNb alloy powders are mainly composed of γ(TiAl) phase and α₂(Ti₃Al) phase. With the decrease of powder size, the cooling rate increases gradually, leading to the decrease of γ(TiAl) phase and the increase of α₂(Ti₃Al) phase. The powder surface with large size shows the dendritic structure, and that with small size is smooth.