急冷雾化法制备金属空心微球研究

Study on Metallic Hollow Spheres Prepared by Rapid Quenching Atomization Method

采用急冷快速凝固实验装置实现了合金熔体的雾化处理,获得了粒径为50μm^800μm的金属空心微球,观察和分析了金属空心微球的结构及球壳组织特征。结果表明,当辊面线速度Vr=30 m/s时,选用Ni-8wt%Pb亚偏晶合金可以获得球形圆整、球壳封闭的金属空心微球、球壳厚度与球径之比在0.15~0.35范围。球壳组织具有典型的快速凝固特征。随着球径的减小,壳厚/球径比减小,冷却速率增大,球壳凝固组织显著细化,由粗大枝晶向等轴晶转变。

The morphology and shell-microstructure of metallic hollow spheres prepared by rapid solidification apparatus which could successfully achieve the spray treatment of alloy melt were observed and analyzed.The particle size was in the range of 50~800 μm,The results indicate that metallic hollow spheres of Ni-8wt%Pb alloy with closed spherical shell and refinement microstructure can be obtained at 30 m/s roller speed,the spherical shell thickness-to-diameter ratio was 0.15~0.35.The microstructures of spherical shell have the typical characteristics of rapid solidification.With the decrease of spherical diameter,the spherical shell thickness-to-diameter ratio reduces,the cooling rate increases and the solidification microstructure of spherical shell tends to refinement,meanwhile,the crystal morphology transforms from dendrite to equiaxed grain.