Martensitic Transformation and Magnetic-Field-Induced Strain in High-Entropy Magnetic Memory Alloy Ni20Mn20Ga20Gd20Co20 by Hot-Magnetic Drawing

• Main Authors: Fang, M. (Author), Ju, J. (Author), Shuai, L. (Author), Yin, K. (Author)
• Format: Article
• Language: English
• Published: MDPI 2022
• Subjects: Cobalt alloys; Entropy; Ferromagnetic materials; Ferromagnetic shape memory; Ferromagnetic-shape memory alloy; ferromagnetic-shape memory alloys; Ferromagnetism; Gadolinium alloys; Gallium alloys; high-entropy magnetic memory alloy; High-entropy magnetic memory alloy; hot-magnetic drawing; Hot-magnetic drawing; Magnetic field-induced strain; Magnetic memory; Magnetic-field; magnetic-field-induced strain; Magnetocaloric effects; Manganese alloys; Martensite; Martensitic transformations; martensitic transition temperature; Martensitic transition temperature; Martensitic transitions; Memory alloy; Ni20Mn20Ga20Gd20Co20; Phase structure; Temperature
• Online Access: View Fulltext in Publisher

 The wires with chemical composition Ni20Mn20Ga20Gd20Co20 were prepared by hot-magnetic drawing and the microstructure evolution characteristics, martensitic transformation and MFIS process were investigated in detail, respectively. The results showed that a multiphase structure with γ phase and martensite was observed in samples when the magnetic field was 0 T to 0.2 T during the hot-magnetic drawing process. With the magnetic field increased to 0.5 T, due to the atomic diffusion by severe thermoplastic deformation and high external magnetic field, a single-phase structure with L10 type twin martensite was found in the sample. Moreover, an obvious increasing trend in martensitic transformation temperature in the sample was found by the enhancement of the magnetic field during the hot-magnetic drawing process. The highest phase transition temperature rose to about 600 °C when the magnetic field reached 0.5 T. Finally, the property of SME and MFIS in the sample can be enhanced by the magnetic field increasing during the hot-magnetic drawing process, excellent performance of SME was obtained at low total strain, and MFIS was achieved at 4.47% at a magnetic field of 8007 Oe in the sample in the 0.5 T magnetic field during the hot-magnetic drawing process. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.