Spheroidisation of metal powder by pulsed electron beam irradiation

Murray, J.W.; Simonelli, M.; Speidel, A.; Grant, D.M.; Clare, A.T.

Abstract

A new powder spheroidisation process has been demonstrated using a large-area, pulsed electron beam technique. This was used to dramatically improve the surface morphology of Stellite 6 metal powder. Powder surface asperities up to 20 μm size can be eliminated by melting and incorporation into the near-surface of the particle. Surface finish is significantly improved. Agitation and rotation of particles due to a beam-induced stress wave enables the irradiation of multiples sides of particles, resulting in uniformly smoothed particles after sufficient pulses. Elemental analysis revealed no measurable contamination as a result of the process. Transmission electron microscopy showed a dense layer is produced within a zone up to 3 μm beneath the surface, with a substantially reduced grain size from ca. 2 μm diameter in the bulk to ca. 40 nm. Elemental homogenisation also was accompanied by grain refinement. The irradiated Stellite 6 showed a reduced basic flowability energy (583 mJ compared to 627 mJ for the untreated), explained by reduced particle-particle cohesion and interlocking, and an increased conditioned bulk density of 4.57 g/ml compared to 4.33 g/ml due to satellite/asperity reduction.

Citation

Murray, J., Simonelli, M., Speidel, A., Grant, D., & Clare, A. (2019). Spheroidisation of metal powder by pulsed electron beam irradiation. Powder Technology, 350, 100-106. https://doi.org/10.1016/j.powtec.2019.03.041

• Journal Article Type: Article
• Acceptance Date: Mar 23, 2019
• Online Publication Date: Mar 26, 2019
• Publication Date: May 15, 2019
• Deposit Date: Nov 14, 2019
• Publicly Available Date: Mar 27, 2020
• Journal: Powder Technology
• Print ISSN: 0032-5910
• Electronic ISSN: 1873-328X
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 350
• Pages: 100-106
• DOI: https://doi.org/10.1016/j.powtec.2019.03.041
• Keywords: General Chemical Engineering
• Public URL: https://nottingham-repository.worktribe.com/output/3285557
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0032591019302165
• Additional Information: This article is maintained by: Elsevier; Article Title: Spheroidisation of metal powder by pulsed electron beam irradiation; Journal Title: Powder Technology; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.powtec.2019.03.041; Content Type: article; Copyright: © 2019 Elsevier B.V. All rights reserved.
• Contract Date: Nov 20, 2019