Founding Research Journal

Founding Research Journal

Effects of Chemical Composition and Heat Treatment Conditions on the ‎Magnetic Properties and Microstructure of Cast Fe–Cr–Co Magnets‎

Document Type : Original Research Article

Authors
1 PhD Student , Department of Materials Engineering, Institute of Mechanical Engineering, University of Tabriz
2 Professor, Department of Materials Engineering, Institute of Mechanical Engineering, University of Tabriz ‎
10.22034/frj.2020.222948.1115
Abstract
In this study two Fe-Cr-Co base alloys with typical compositions Fe-28Cr-15Co-1 Si (alloy A) and Fe-32Cr-23Co-1 Si (alloy B) were prepared by casting technique and anisotropic permanent magnets were produced by applying some special heat treatments. Studies revealed that the magnetic properties of investigated alloys are very low in as-cast and in solution annealed conditions but are significantly enhanced by applying TMT. The presence of a sideband alongside the (110) reflection peak in X-ray diffraction pattern after TMT demonstrated that spinodal decomposition was occurred in this stage of heat treatment. During the step aging treatment, chemical compositions of the two spinodal phases (α1 and α2) are changed which results in an increase in Jsα1- Jsα2 and therefore, the coercivity is increased. Moreover this study revealed that magnetic properties obtained in Fe-28Cr-15Co-1Si alloy was as Br = 0.72 T, Hc = 60.50 kA/m and (BH) max= 31.19 kJ/m3 and was higher than Fe-32Cr-23Co-1Si. Microstructural investigations showed that in the Fe-32Cr-23Co-1Si alloy with a higher chromium percentage, the non-magnetic sigma phase was formed, leading to a decrease in the magnetic properties.
Keywords
Subjects

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  • Receive Date 10 March 2020
  • Revise Date 28 April 2020
  • Accept Date 29 April 2020