BCMaterials lecture at HTSMAs 2015

Volodymyr Chernenko will participate at the HTSMAs 2015 International Conference, on May the 7th, at Wildbad Kreuth, Germany. You can download the flyer here. Ni-Mn-Ga high temperature shape memory alloys V.A. Chernenko1,2, E. Villa3,  J.M.Barandiaran1,V.A. L´vov4 1 BCMaterials &  Universidad del País Vasco, UPV/EHU, P.O. Box 644, Bilbao 48080, Spain 2 Ikerbasque, Basque Foundation for Science, Bilbao 48013, Spain 3 CNR-IENI, C.Promessi Sposi 29, Lecco 23900, Italy 4 Institute of Magnetism, Kyiv 03142, Ukraine It is well-known that the temperature of the thermoelastic martensitic transformation (MT) in Heusler Ni2MnGa intermetallic compound can be tuned in the extremely wide range from close to 0 K up to 700 K and higher, simply by manipulating of the atomic percentage of the element constituents [1]. By the tensile dynamical and quasi-static testing of the off-stoichiometric Ni-Mn-Ga single crystals, recently we have demonstrated their outstanding shape memory, two-way shape memory and superelastic characteristics in the temperature range of 573-673 K [2]. In this presentation we will focus on the different physical aspects of the transformation behavior of these materials, such as martensite destabilization effects during thermal, mechanical and combined thermomechanical cycling through MT and related internal friction and fatigue properties. The theoretical analysis in the framework of Landau theory revealed that the observed cyclic-induced effects can be quantified in terms of the influence of internal stress existing due to the presence of defects of any nature and their reconfiguration in the process of alloy treatments. [1] V. A. Chernenko, E. Cesari, V. V. Kokorin, and I. N. Vitenko. Scr. Metall. Mater. 33, 1239 (1995). [2] V. A. L’vov, A. Kosogor, J. M. Barandiaran, V. A. Chernenko, Acta Mater. 60, 1587 (2012).