Martensitic Transformation, Structure and Magnetic Properties of Co-Ni-Ga Ferromagnetic Shape Memory Alloys

Abstract:

In the present paper the effect of heat treatment on microstructure, martensitic transformation temperatures and magnetic properties behavior of Co-Ni-Ga pollycrystal was discussed in detail. Microscopic observations revealed two types of two phase polycrystalline alloys: i) martensite with γ-precipitates and ii) parent phase with γ-precipitates. Making use of Xray and electron diffraction methods the crystal structure of martensite phase was identified as bct structure (with co/ao about 1.2). Annealing of Co-Ni-Ga alloy at 1223K/40 min causes a separation of martensitic and magnetic transformation and an increase of the Curie temperature by about 70K, after this annealing any significant structural changes in the parent (martensitic) and γ phase are not observed.

• Periodical: Solid State Phenomena (Volume 130)
• Pages: 141-146
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.130.141
• Online since: December 2007
• Authors: B. Kostrubiec, Krystian Prusik, Ł. Madej, Henryk Morawiec
• Keywords: Ferromagnetic Shape Memory Alloys (FSMAs), Gamma Phase, Two Phase

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