Print Email Facebook Twitter Exploring the negative thermal expansion and magnetocaloric effect in Fe2(Hf,Ti) Laves phase materials Title Exploring the negative thermal expansion and magnetocaloric effect in Fe2(Hf,Ti) Laves phase materials Author Shen, Q. (TU Delft RST/Fundamental Aspects of Materials and Energy) Batashev, I. (TU Delft RST/Fundamental Aspects of Materials and Energy; Radboud Universiteit Nijmegen) Zhang, F. (TU Delft RST/Fundamental Aspects of Materials and Energy) Ojiyed, Hamutu (External organisation) Dugulan, A.I. (TU Delft RST/Fundamental Aspects of Materials and Energy; TU Delft RID/TS/Instrumenten groep) van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy) Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy) Date 2023 Abstract The transition-metal based Laves phase materials represent an extended family of alloys with rich and fascinating physical properties. In this work, we have investigated the negative thermal expansion and magnetocaloric effect in arc-melted and melt-spun Fe2Hf1-xTix (x = 0.15, 0.27, 0.30, 0.33, 0.36, 0.40) alloys. For x = 0.30–0.40, two hexagonal phases with different compositions share the same P63/mmc lattice symmetry, but have slightly different lattice parameters. The saturation magnetization and Curie temperature both follow a decreasing trend with the average unit-cell volume. For Fe2Hf0.6Ti0.4 melt spinning improves the saturation magnetization from 48.7 to 59.6 Am2/kg and the magnetic entropy change from 0.46 to 0.54 J/kgK at a magnetic field change of 2 T. These enhanced values are attributed to an improved homogeneity caused by a suppression of phase segregation during rapid solidification. We have utilized neutron powder diffraction and Mössbauer spectroscopy to illustrate the correlation between the magnetic order and the negative thermal expansion in single-phase Fe2Hf0.85Ti0.15. The magnetic moments of Fe align below 400 K in the a-b plane and a moment change for the Fe atoms is responsible for the large volumetric coefficient of thermal expansion of −25 × 10−6 K−1 over a wide temperature range of 300–400 K. Subject Magnetocaloric effectNegative thermal expansionNeutron diffractionSecond-order phase transition To reference this document use: http://resolver.tudelft.nl/uuid:7289a4ad-77c2-49eb-9766-7b30df63cb7e DOI https://doi.org/10.1016/j.actamat.2023.119149 ISSN 1359-6454 Source Acta Materialia, 257 Part of collection Institutional Repository Document type journal article Rights © 2023 Q. Shen, I. Batashev, F. Zhang, Hamutu Ojiyed, A.I. Dugulan, N.H. van Dijk, E.H. Brück Files PDF 1_s2.0_S1359645423004809_main.pdf 7.41 MB Close viewer /islandora/object/uuid:7289a4ad-77c2-49eb-9766-7b30df63cb7e/datastream/OBJ/view