无坩埚熔炼气雾化技术制备Ti6Al4V粉末

Preparation of Ti6Al4V powder with high yield of fine particle by crucible-less gas atomization technology

摘要:

本论文采用自主研发设计的无坩埚熔炼气雾化设备制备适用于金属增材制造的球形Ti6Al4V粉末。通过调节进料速度与雾化压力，45μm以下的粉末收得率可达35 wt.%，高于旋转电极制粉的收的率（~10 wt.%）通过扫描电子显微镜（SEM）、X射线衍射（XRD）和金相显微镜（OM）表征粉末显微结构与组织。结果表明制备的Ti6Al4V粉末具有良好的球形度和表面光滑，良好的流动性和较高的松装密度使其可用于金属增材制造与注射成型等。由于雾化过程中粉末的冷却速度为 104-108 K/s，粉末中的β相在冷却过程中转变为针状α′ 相。

Abstract:

This study aims at producing sphere Ti6Al4V powders with tailed physical characteristics for additive manufacturing application. Ti6Al4V powders were prepared by a novel electrode induction guiding gas atomization (EIGA) equipment designed independently. The yielding rate of fine powders could be improved by reasonably increasing feed rate and atomization gas pressure. Interestingly, the yield (35%) of powder particles below 45μm by EIGA is significantly higher than the yield (~ 10%) by conventional plasma rotating electrode technology. The powder properties and microstructure were characterized by scanning electron microscope (SEM), X ray diffraction (XRD) and optical microscope (OM). The powders exhibited satisfactory flowability and high apparent density for good sphericity and smooth surface. The powders with tailed size ranges could be used for various additive manufacturing methods and injection moulding etc. The β phase of Ti6Al4V translates to needle-like α′ phase during atomization process because of fast cooling rate calculated to be 104-108 K/s.