Study of Martensitic Transformation Temperatures of Ferromagnetic Shape Memory NiMnGa Alloys

Abstract:

As a new class of shape memory alloy, Ni₂MnGa ferromagnetic shape memory alloy (FSMA) has both large reversible strain and higher response frequency, which has attracted considerable attention and has been widely investigated.The martensitic transformations temperatures of the as-cast Ni₂MnGa alloys are investigated by differential scanning calorimeter (DSC). Following conclusions were obtained from experimental results: By using DSC measurement, martensite transformation temperatures (including M_s, M_f, A_s and A_f) were obtained in two alloy series of Ni_51.5+xMn_23.5Ga_25-x and Ni_51.5Mn_23.5+yGa_25-y. Results showed that: martensite transformation temperatures enhanced with the Ni and Mn increasing respectively, and the effect is stronger for Ni than Mn. After 600°C vacuum annealing 6h using powder samples, the martensitic transformation temperature was slight lower than as-cast state.

• Periodical: Applied Mechanics and Materials (Volume 364)
• Pages: 537-541
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.364.537
• Online since: August 2013
• Authors: Gen Zong Song, Duo Zhang
• Keywords: Ferromagnetic Shape Memory, Martensitic Transformation (MT), Transformation Temperature

References

[1] A. Sozinov, A.A. Likhachev and N. Lanska: Appl Phys Lett, (2002), 80, p.1746.

[2] R.C. O'handley: Appl Phys, (1998), 83, p.3263.

[3] R. Kainuma, Y. Imano and W. Ito: Nature, (2006), 11, p.957.

[4] J. Pons, V.A. Chernenko and R. Santamarta: Acta Materialia, (2000), 48, p.3027.

[5] G.H. Wu, W.H. Wang and J.L. Chen: App Phys Lett, (2002), 80, p.634.

[6] B. Wedel, M. Suzuki and Y. Murakami: Alloys and Compounds, (1999) 290, p.137.