Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/81588
Title: Formation of fully equiaxed grain microstructure in additively manufactured AlCoCrFeNiTi0.5 high entropy alloy
Authors: Guan, S 
Solberg, K
Wan, D
Berto, F
Welo, T
Yue, TM 
Chan, KC 
Keywords: Additive manufacturing
AlCoCrFeNiTi0.5 high entropy alloy
Dendrite fragmentation
Equiaxed grain formation
Eutectic reaction
Nucleation
Issue Date: 2019
Publisher: Elsevier
Source: Materials and design, 2019, v. 184, 108202 How to cite?
Journal: Biology 
Abstract: In this work, the non-equiatomic high entropy alloy AlCoCrFeNiTi0.5 was additively manufactured via the laser engineered net shaping (LENS™) process. Contrary to the columnar grain microstructure commonly observed in previously reported alloys, the as-deposited AlCoCrFeNiTi0.5 specimens exhibit a fully equiaxed grain microstructure in a wide range of temperature gradients G (85 to 1005 K/mm) and solidification velocities V (5 to 20 mm/s). The main microstructural characteristics were found to be B2-structured proeutectic dendrites delineated by lamellar or rod-like B2/A2 eutectic structures. The formation of this microstructural feature can be discussed with the aid of Scheil's solidification model. The proeutectic B2-structured dendrites were frequently found to be fragmented, which may provide profuse effective nucleation sites, and hence promote equiaxed grain formation. Furthermore, we estimated the volume fraction ϕ values of equiaxed crystals at solidification front for various G - V combinations established in this paper, which can provide a theoretical basis for our experimental findings. The current work provides guidelines for producing fully equiaxed alloys by the additive manufacturing (AM) process.
URI: http://hdl.handle.net/10397/81588
ISSN: 0264-1275
EISSN: 1873-4197
DOI: 10.1016/j.matdes.2019.108202
Rights: © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
The following publication Guan, S., Solberg, K., Wan, D., Berto, F., Welo, T., Yue, T. M., & Chan, K. C. (2019). Formation of fully equiaxed grain microstructure in additively manufactured AlCoCrFeNiTi0. 5 high entropy alloy. Materials & Design, 184, 108202, is available at https://doi.org/10.1016/j.matdes.2019.108202
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