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Journal of Materials Science

, Volume 14, Issue 10, pp 2296–2302 | Cite as

Decomposition of the Heusler alloy Cu2MnAl at 360°C

  • Bernard Dubois
  • Dominique Chevereau
Papers

Abstract

During thermomagnetic studies, the as-quenched Heusler alloy Cu2.00 Mn1.00 Al1.01 exhibits two Curie temperatures \(\theta _{C_I } \) and \(\theta _{C_{II} } \). After 98 h at 360° C, above the Curie point, X-ray diffraction patterns indicate two ferromagnetic phases: Cu2MnAl (I) withaI=5.8707 Å and \(\theta _{C_I } \) = 151 ± 10° C; Cu2MnAl (II) withaII=5.9656 Å and \(\theta _{C_{II} } \) = 332 ± 4° C, whereas the 850° C as-quenched alloy exhibitsa=5.9612 Å andθc=341±5° C.

The results are discussed in terms of the early stages of the decomposition of the Heusler phase. A mechanism, involving mainly the atomic migration of manganese, is suggested in order to reach the equilibrium phases of the ternary Cu-Mn-Al diagram. The kinetics of the decomposition should be ruled by the nucleation and the growth of the Cu3Mn2Al intermetallic compound.

Keywords

Intermetallic Compound Curie Temperature Curie Point Equilibrium Diagram Ferromagnetic Phasis 

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Copyright information

© Chapman and Hall Ltd. 1979

Authors and Affiliations

  • Bernard Dubois
    • 1
  • Dominique Chevereau
    • 1
  1. 1.Laboratoire de MétallurgieEcole Nationale Superieure de ChimieParis, Cedex 05France

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