Abstract
A novel refractory high-entropy alloy (RHEA) spherical powder WTaMoNbZr was synthesized successfully through four-steps: melting, hydrogenation, crushing and spheroidization. The alloy ingot with ~110 mm in diameter and ~120 mm in height was prepared by vacuum electron beam melting. The ingot formed a single body-centered cubic (BCC) solid solution phase, with lattice parameters of 3.244 Å, thereby possessing a good combination of compressive stress (1973 MPa) and strain (17.63%). And this increased the difficulty to pulverize it into fine powder. It was found that hydrogenated treatment can embrittle the ingot, and irregular powders with the particle size ranging from 1.56 µm to 59.5 µm were then easily obtained by using a disk crusher. Finally, highly spheroidized RHEA powders with spheroidization ratio of 95.3% were fabricated by plasma spheroidization. After the plasma treatment, the powders possessed an average particle size of 37.5 µm and a single BCC phase structure was also obtained. The flow property and apparent density were 15.09 s•(50 g)−1 and 7.42 g•cm−3 respectively, indicating a better spheroidization effect. The nano-microhardness of the RHEA powder was 7.99 GPa, which was about 1.68 GPa higher than that of the bulky RHEA with the same composition. These excellent properties endow RHEA powder with broader potential applications, such as protective coatings, additive manufacturing. More importantly, this study provides a new approach to prepare spherical RHEA powder, which is of great significance for the further development.
Published Version
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