Effects of Thermo-magnetic Heat Treatment on Microstructure and Magnetic Properties...

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Effects of Thermo-magnetic Heat Treatment on Microstructure and Magnetic Properties of Alnico 5DG Alloy K. Nekoee, S. Heshmati Maneh, A. Ataie Department of Metallurgy & Materials, University of Tehran, Tehran, Iran. E-mail: [email protected] Abstract: In this research, Alnico 5DG alloy was melt and cast in the optimum conditions and its samples were homogenised and heat treated in a magnetic field in order to obtain the required magnetic properties. Microstructure, phase composition and magnetic properties of samples were examined in every processing step. The results indicated that the properties of samples were highly influenced by processing parameters. A proper microstructure composed of 1 magnetic phase in a texture of 2 with acceptable magnetic properties was obtained by meticulous control of the processing conditions. The results also revealed that the magnetic coercivity (and remanence) of the cast samples should be increased by an appropriate heat treatment from 12 kA/m (and 0.55 T) to 41.6 kA/m (and 1.3 T), respectively. Keywords: Magnetic materials, Directional solidification, Alnico 5DG, Phase composition. Vol. 12, No. 1, 1383/2004 Spring & Summer (received: 24/8/2003, received in revised form: 14/3/2004) Downloaded from ijcm.ir at 19:01 +0430 on Sunday September 20th 2020

Transcript of Effects of Thermo-magnetic Heat Treatment on Microstructure and Magnetic Properties...

Page 1: Effects of Thermo-magnetic Heat Treatment on Microstructure and Magnetic Properties …ijcm.ir/article-1-757-fa.pdf · acceptable magnetic properties was obtained by meticulous control

Effects of Thermo-magnetic Heat Treatment on Microstructure and Magnetic Properties

of Alnico 5DG Alloy

K. Nekoee, S. Heshmati Maneh, A. Ataie

Department of Metallurgy & Materials, University of Tehran, Tehran, Iran. E-mail: [email protected]

Abstract: In this research, Alnico 5DG alloy was melt and cast in the optimum conditions and its samples were homogenised and heat treated in a magnetic field in order to obtain the required magnetic properties. Microstructure, phase composition and magnetic properties of samples were examined in every processing step. The results indicated that the properties of samples were highly influenced by processing parameters. A proper microstructure composed of α1 magnetic phase in a texture of α2 with acceptable magnetic properties was obtained by meticulous control of the processing conditions. The results also revealed that the magnetic coercivity (and remanence) of the cast samples should be increased by an appropriate heat treatment from 12 kA/m (and 0.55 T) to 41.6 kA/m (and 1.3 T), respectively.

Keywords: Magnetic materials, Directional solidification, Alnico 5DG, Phase composition.

Vol. 12, No. 1, 1383/2004 Spring & Summer

(received: 24/8/2003, received in revised form: 14/3/2004)

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Q=,� [1] Mc Curri R.A., “Ferromagnetic Materials: A Handbook on the properties of magnetically ordered substances”, Vol. 3, ed. Ep. Wohlfarth, North – Holland, Amsterdam (1982) pp. 111-184. [2] Devos K.J., “Alnico Permanent Magnet Alloys, in Magnetism and Metallurgy”, Vol. 1, Academic Press, New York, London (1969) PP. 473-512.[3] Graham Jr C.D., “Textured Magnetic Materials, in Magnetism and Metallurgy”, Vol. 2, Academic Press, New York, London (1969) pp. 723-748.

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[4] Pramanik S., Rao V., Monantj O.N., “Effect of niobium on the directional solidification and properties of Alnico alloys”, J. Mater. Sci. (1993) Vol. 28, pp. 1237-1244. [5] Szymura S., Golba S., “The influence of niobium on the magnetic properties of the columnar Alnico5 permanent magnets”, J. Magn. Magn. Mater. No. 24 (1981) pp. 285-287. [6] Szymura S., “The effect of boron on the magnetic properties of Alnico5 permanent magnet Alloys”, Mat. Chem. Phys. No. 13 (1985) pp. 489-495. [7] Kuznetsov V.M., “Alloying of Fe-Co-Ni-Al-Cu system (English Translation of Metallovedente in Termicheskey Obrabot ka Metallov), Vol. 29, No. 3-4 (1987) pp. 308-311. [8] Steinorth E., “Monocrystalline permanent magnets and method of making them”, U. S. Patent, No. 3085036, April (1963).

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