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Abstract

Materials with so-called soft magnetic properties are an important object of material engineering research due to their potential application, among others, in the construction of low-loss transformer cores. Such properties are typical for alloys with an amorphous structure and with a high content of ferromagnetic elements: Fe, Co, Ni. Difficulties related with obtaining alloys which meet satisfactory dimensions result in the search for new solutions. One of them is the production of composites based on ferromagnetic powders obtained from amorphous alloys. This paper presents results of structure research for composite materials produced in a multi-stage production process. Magnetic composites were made on the basis of a bulk amorphous Fe70B20Y5Nb4Mo1 alloy produced by the injection method. On the basis of the obtained powder, two series of moldings were made: with 0.5% resin and covered with high-temperature varnish. Final composites were produced by using high temperature isostatic press. On the basis of the conducted research, it was found that the composites without resin are characterized by distinctly better magnetic properties as compared to resin-bonded composites.
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Authors and Affiliations

Bartłomiej Jeż
1
ORCID: ORCID
Przemysław Postawa
1
Marcin Nabiałek
2
ORCID: ORCID

  1. Department of Technology and Automation, Faculty of Mechanical Engineering and Computer Science, Czestochowa University of Technology, al. Armii Krajowej 19c, 42-200 Czestochowa, Poland
  2. Department of Physics, Faculty of Production Engineering and Materials Technology, Czestochowa University of Technology, al. Armii Krajowej 19, 42-200 Czestochowa, Poland
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Abstract

This study aimed to prepare Zr55Cu30Al10Ni5 bulk amorphous alloys by spark plasma sintering of raw amorphous alloy powders and investigate their microstructure and micromechanical behaviors. When the sintering temperature ( Ts) was 675K, which was lower than the glass transition temperature ( Tg) of the material, the sintered sample was almost fully amorphous but the density was lower. However, when Ts was 705K, which was higher than Tg, partial crystallization occurred, but the density was higher. The hardness of the bonding zone of the sintered sample at 675K was 5.291 GPa due to the lower density, which was lower than that at 705K, and the hardness at 705K was 8.836 GPa. The generation of thermodynamically stable intermetallic phases, the hardness, and the elastic modulus of the samples sintered above Tg were higher due to the higher density.
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Authors and Affiliations

Yaqiong Ge
1
Zexin Chang
1
Wenxian Wang
1
Qingling Hou
1

  1. Taiyuan University of Science and Technology, College of Materials Science and Engineering, Taiyuan 030024, China
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Abstract

This article presents the results of tests carried out on rapid quenched Fe-based alloys. The alloys were made using an injection-casting method. The actual structure of the alloys was also studied using an indirect method, based on H. Kronmüller's theorem. Based on analysis of the primary magnetization curves, in accordance with the aforementioned theory, it was found that Mo causes a change in internal regions associated with changes in the direction of the magnetization vector. The evolution of the thermal properties with increasing volume of Mo has been confirmed by the DSC curves. Addition of Mo, at the expense of the Nb component, results in changes to the crystallization process (i.e. the crystallization onset temperature and number of stages). The study showed that the addition of Mo at the expense of Nb reduces glass forming ability. Based on the DSC analysis, free volumes were determined for the alloys tested. These values were compared with the analysis of primary magnetization curves. It was found that the DSC curves can be used to indirectly describe the structure of amorphous alloys similar to the theory of the approach to ferromagnetic saturation. This approach is new and can be used by many researchers in this field.
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Authors and Affiliations

Bartłomiej Jeż
1
ORCID: ORCID
Marcin Nabiałek
2
ORCID: ORCID

  1. Department of Technology and Automation, Faculty of Mechanical Engineering and Computer Science, Czestochowa University of Technology, al. Armii Krajowej 19c, 42-200 Czestochowa, Poland
  2. Department of Physics, Faculty of Production Engineering and Materials Technology, Czestochowa University of Technology, al. Armii Krajowej 19, 42-200 Cz ̨estochowa, Poland

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