Comparative Study on Preparation of Aluminum-Rare Earth Master Alloy Fine Powders by Mechanical Pulverization and Gas Atomization Methods

Aiming at the high-value application of rare earth elements lanthanum (La), an Al-50% La alloy was selected and prepared in a vacuum medium-frequency induction furnace. The geometric characteristics of the Al-50% La alloy powders were compared and studied, with the powders prepared by two different methods: mechanical pulverization and gas atomization. The results showed that an Al-49.09% La master alloy was obtained, and the only intermediate phase containing La in the experimental alloy was Al11La3. From the perspectives of chemical and phase composition, La has a high yield. Additionally, an Al-La alloy with controllable rare earth intermediate phases can be obtained. The Al-La alloy powders prepared by the mechanical pulverization method are irregular in shape, but the particle size is relatively small, ranging from 0.25 to 66.9 μm. Submicron powders were obtained, with 4.38% of the powders having an equivalent particle size of less than 1 μm. Considering the characteristic of the selective laser melting (SLM) process forming micro-melt pools, a small amount of submicron Al-La alloy powders prepared by the mechanical pulverization method can be used as a trace additive for SLM preparation of CP-Ti. The powders prepared by gas atomization have good sphericity, with a particle size range of 1.65 to 76.0 μm. Among them, the powders with a size of 2–10 μm account for 75.52%, and this part of the powders can be used for the powder metallurgy preparation of composite materials.