Metallurgical Processing of CoCrFeNi High-Entropy Alloy
DOI:
https://doi.org/10.24425/afe.2024.151310Abstract
High-entropy alloys (HEA) is a group of metallic materials that is currently experiencing great development in materials science. While conventional alloys are based on a majority of a primary element with some number of added elements, HEAs are based on multiple (usually more than 5) elements that reach equimolar/equiatomic content. With the right combination of elements, properties can be achieved that could predispose HEAs for practical applications. In the fabrication of HEAs in previous research, pure metals have been predominantly used as the charging material. However, the use of common industrial charge with limited purity is crucial for the more economically viable use of HEAs in industry. Such a charge material may contain accompanying elements which may have an undesirable effect on the properties of the alloy. In order to achieve optimum alloy properties, it is necessary to minimise their content using various metallurgical processes. The aim of the work was the metallurgical processing of CoCrFeNi alloy melted from scrap metal in an induction furnace. The desired reduction of carbon (to 100 ppm) and nitrogen content (from 660 to ~60 ppm) was reached by using carbon reaction under vacuum. Significant reduction in oxygen content (to ~120 ppm) was reached after a deoxidation with aluminium and slight reduction in sulphur content (~25%, to 120 ppm) was reached after a desulphurisation with rare earth metals.References
[1] Miracle, D.B. & Senkov, O.N. (2017). A critical review of high entropy alloys and related concepts. Acta Materialia. 122, 448-511. https://doi.org/10.1016/j.actamat.2016.08.081.
[2] Murty, B.S., Yeh, J.W., Ranganathan, S. & Bhattacharjee, P.P. (2019). High-entropy alloys: basic concepts. High-Entropy Alloys (Second Edition). 13-30. https://doi.org/10.1016/B978-0-12-816067-1.00002-3.
[3] Alshataif, Y.A., Sivasankaran, S., Al-Mufadi, F.A., Alaboodi, A.S. & Ammar, H.R. (2020). Manufacturing methods, microstructural and mechanical properties evolutions of high-entropy alloys: a review. Metals and Materials International. 26(8), 1099-1133. https://doi.org/10.1007/s12540-019-00565-z.
[4] Chao, Q., Joseph, J., Annasamy, M., Hodgson, P., Barnett, M.R. & Fabijanic, D. (2024). AlxCoCrFeNi high entropy alloys from metal scrap: Microstructure and mechanical properties. Journal of Alloys and Compounds. 976, 173002, 1-13. https://doi.org/10.1016/j.jallcom.2023.173002.
[5] Hariharan, K. & Sivaprasad, K. (2022). Sustainable low-cost method for production of high-entropy alloys from alloy scraps. Journal of Sustainable Metallurgy. 8(2), 625-631. https://doi.org/10.1007/s40831-022-00523-x.
[6] Baker, I. (2020). Interstitials in FCC high entropy alloys. Metals. 10(5), 695, 1-20. https://doi.org/10.3390/met10050695.
[7] Briant, C.L., Banerji, S.K. & Ritter, A.M. (1982). The role of nitrogen in the embrittlement of steel. Metallurgical Transactions A. 13(11), 1939-1950. https://doi.org/10.1007/BF02645939.
[8] Zhao, D., Yang, Q., Wang, D., Yan, M., Wang, P., Jiang, M., Liu, C., Diao, D., Lao, C., Chen, Z., Liu, Z., Wu, Y. & Lu, Z.(2020). Ordered nitrogen complexes overcoming strength–ductility trade-off in an additively manufactured high-entropy alloy. Virtual and Physical Prototyping.15(sup1), 532-542. https://doi.org/10.1080/17452759.2020.1840783.
[9] Wang, R., Tang, Y., Lei, Z., Ai, Y., Tong, Z., Li, S., Ye, Y. &Bai, S. (2022). Achieving high strength and ductility in nitrogen-doped refractory high-entropy alloys. Materials & Design. 213, 110356, 1-14. https://doi.org/10.1016/j.matdes.2021.110356.
[10] da Costa e Silva, A.L.V. (2019). The effects of non-metallic inclusions on properties relevant to the performance of steel in structural and mechanical applications. Journal of Materials Research and Technology. 8(2), 2408-2422. https://doi.org/10.1016/j.jmrt.2019.01.009.
[11] Choi, N., Lim, K.R., Na, Y.S., Glatzel, U. &Park, J.H. (2018).Characterization of non-metallic inclusions and their influence on the mechanical properties of a FCC single-phase high-entropy alloy. Journal of Alloys and Compounds. 763, 546-557. https://doi.org/10.1016/j.jallcom.2018.05.339.
[12] Laurent-Brocq, M., Akhatova, A., Perrière, L., Chebini, S., Sauvage, X., Leroy, E. & Champion, Y. (2015). Insights in to the phase diagram of the CrMnFeCoNi high entropy alloy. Acta Materialia. 88, 355-365. https://doi.org/10.1016/j.actamat.2015.01.068.
[13] Zhao, L., Jiang, L., Yang, L.X., Wang, H., Zhang, W.Y., Ji, G.Y., Zhou, X., Curtin, W.A., Chen, X.B., Liaw, P.K.,Chen, S.Y. & Wang, H.Z. (2022). High throughput synthesis enable dexploration of CoCrFeNi-based high entropy alloys. Journal of Materials Science & Technology. 110, 269-282. https://doi.org/10.1016/j.jmst.2021.09.031.
[14] Bůžek,Z.(1979). Metallurgicalnews: Basic thermodynamic data on metallurgical reactions and interactions of elements in systems important for metallurgical theory and practice. Hutnické Aktuality, 1. (in Czech).
