Singh, Nidhi and Mudgil, Varun and Anand, Kanika and Srivastava, A. K. and Kotnala, R. K. and Dhar, Ajay (2015) Influence of processing on structure property correlations in iota-MnAl rare-earth free permanent magnet material. Journal of Alloys and Compounds, 633. pp. 401-407. ISSN 0925-8388

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In order to understand the genesis of the magnetic tau-phase of MnAl alloy, which due to its multiphase nature is generally difficult to synthesize as a single-phase, we have synthesized it employing three different materials processing routes, namely, arc melting, mechanical alloying, and a combination of these two. Structural and microstructural characterizations employing X-ray diffraction and high resolution transmission electron microscopy demonstrate that irrespective of the material processing route employed, the formation of tau-MnAl phase was always accompanied by other non-magnetic phases, e.g., beta-MnAl and gamma-MnAl. However, the relative fraction of these phases was found to be dependent on the materials processing route and hence on the grain size of the parent phase. The arc melted alloy had the largest grain size and the highest fraction of the tau-MnAl phase, while the alloy prepared by mechanical alloying showed the smallest grain size and the lowest fraction of the magnetic phase. The largest value of Curie temperature, magnetic moment, coercivity and remanence were observed in the sample prepared by a combination of arc melting and mechanical alloying. Our results suggest that in addition to the tau-MnAl phase fraction the magnetic properties could be related to the density of structural defects.

Item Type: Article
Uncontrolled Keywords: MnAl hard magnets Rare-earth free permanent magnets Structure–property correlations Mechanical alloying Arc melting
Subjects: Chemistry > Physical Chemistry
Materials Science
Metallurgy & Metallurgical Engineering
Depositing User: Dr. Rajpal Walke
Date Deposited: 28 Sep 2016 05:56
Last Modified: 28 Sep 2016 05:56

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