Journal of Materials Science

, Volume 24, Issue 11, pp 4088–4093

Phase transformations in Mn-Al permanent magnet alloys

  • V. Rao
  • S. Pramanik
  • C. R. Tewari
  • S. R. Singh
  • O. N. Mohanty
Article

Abstract

Phase transformation studies have been made of the Mn-Al alloys with compositions near the equiatomic range with or without small amounts of carbon, copper and nickel, using differential thermal analysis, X-ray diffraction and optical and electron microscopy. The high temperature hexagonalɛ phase obtained by quenching, transforms to the ferromagneticτ phase between 500 and 550° C and on further heating transforms back to the hexagonal phase between 750 and 950° C. Also, on controlled cooling of theɛ phase from about 900° C, the ferromagneticτ phase is formed between 800 and 670° C. TEM studies have shown the presence of the B19 ordered phase, ferromagneticτ phase and Mn5Al8 precipitates even in quenched alloys.

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Copyright information

© Chapman and Hall Ltd 1989

Authors and Affiliations

  • V. Rao
    • 1
  • S. Pramanik
    • 1
  • C. R. Tewari
    • 1
  • S. R. Singh
    • 1
  • O. N. Mohanty
    • 1
  1. 1.National Metallurgical LaboratoryJamshedpurIndia

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