Qi Hang, Zhou Xianglin, Li Jinghao, Hu Yunfei, Xu Lianghui
State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China.
Department of Mechanical Engineering, McGill University, Montreal, QC H2A 0C3, Canada.
Materials (Basel). 2021 Sep 9;14(18):5188. doi: 10.3390/ma14185188.
Gas atomization is a widely used method to produce the raw powder materials for additive manufacturing (AM) usage. After the metal alloy is melted to fusion, gas atomization involves two relatively independent processes: liquid breakup and droplet solidification. In this paper, the solidification behavior of powder during solidification is analyzed by testing the powder's properties and observing microstructure of a martensitic stainless steel (FeCrNiBSiNb). The powder prepared by gas atomization has high sphericity and smooth surface, and the yield of qualified fine powder is 35%. The powder has typical rapid solidification structure. Collision between powders not only promotes nucleation, but also produces more satellite powder. The segregation of elements in powder is smaller as the result of high cooling rate which can reaches 4.2 × 10 K/s in average. Overall, the powder prepared by gas atomization is found to have good comprehensive properties, desired microstructure, and accurate chemical component, and it is suitable for various additive manufacturing techniques.
气体雾化是一种广泛用于生产增材制造（AM）用原料粉末的方法。金属合金熔化至熔融状态后，气体雾化涉及两个相对独立的过程：液体破碎和液滴凝固。本文通过测试马氏体不锈钢（FeCrNiBSiNb）粉末的性能并观察其微观结构，分析了粉末凝固过程中的凝固行为。通过气体雾化制备的粉末具有高球形度和光滑表面，合格细粉的产率为35%。该粉末具有典型的快速凝固组织。粉末之间的碰撞不仅促进形核，还会产生更多的卫星粉。由于平均冷却速率可达4.2×10 K/s，粉末中元素的偏析较小。总体而言，发现通过气体雾化制备的粉末具有良好的综合性能、理想的微观结构和准确的化学成分，适用于各种增材制造技术。
