The effect of hydrogen on the multiscale mechanical behaviour of a La(Fe,Mn,Si)13-based magnetocaloric material

Wang, Siyang; Gavalda-Diaz, Oriol; Luo, Ting; Guo, Liya; Lovell, Edmund; Wilson, Neil; Gault, Baptiste; Ryan, Mary P.; Giuliani, Finn

Abstract

Magnetocaloric cooling offers the potential to improve the efficiency of refrigeration devices and hence cut the significant CO2 emissions associated with cooling processes. A critical issue in deployment of this technology is the mechanical degradation of the magnetocaloric material during processing and operation, leading to limited service-life. The mechanical properties of hydrogenated La(Fe,Mn,Si)13-based magnetocaloric material are studied using macroscale bending tests of polycrystalline specimens and in situ micropillar compression tests of single crystal specimens. The impact of hydrogenation on the mechanical properties are quantified. Understanding of the deformation/failure mechanisms is aided by characterization with transmission electron microscopy and atom probe tomography to reveal the arrangement of hydrogen atoms in the crystal lattice. Results indicate that the intrinsic strength of this material is ~3–6 GPa and is dependent on the crystal orientation. Single crystals under compressive load exhibit shearing along specific crystallographic planes. Hydrogen deteriorates the strength of La(Fe,Mn,Si)13 through promotion of transgranular fracture. The weakening effect of hydrogen on single crystals is anisotropic; it is significant upon shearing parallel to the {111} crystallographic planes but is negligible when the shear plane is {001}-oriented. Atom probe tomography analysis suggests that this is associated with the close arrangement of hydrogen atoms on {222} planes.

Citation

Wang, S., Gavalda-Diaz, O., Luo, T., Guo, L., Lovell, E., Wilson, N., …Giuliani, F. (2022). The effect of hydrogen on the multiscale mechanical behaviour of a La(Fe,Mn,Si)13-based magnetocaloric material. Journal of Alloys and Compounds, 906, Article 164274. https://doi.org/10.1016/j.jallcom.2022.164274

• Journal Article Type: Article
• Acceptance Date: Feb 18, 2022
• Online Publication Date: Feb 19, 2022
• Publication Date: Jun 15, 2022
• Deposit Date: Nov 7, 2022
• Publicly Available Date: Nov 7, 2022
• Journal: Journal of Alloys and Compounds
• Peer Reviewed: Peer Reviewed
• Volume: 906
• Article Number: 164274
• DOI: https://doi.org/10.1016/j.jallcom.2022.164274
• Keywords: Materials Chemistry; Metals and Alloys; Mechanical Engineering; Mechanics of Materials
• Public URL: https://nottingham-repository.worktribe.com/output/13181132
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S092583882200665X