Reactive Stresses and Burst Character of Shape Memory Deformation in Single Crystals Cu-Al-Ni and Ni-Fe-Ga Single Crystals

Abstract

Abstract. The paper is a presentation of two new phenomena which have been recently revealed and investigated by authors in well-known shape memory alloys such as Cu-Al-Ni and Ni-Fe-Ga. The first is a strong decrease of the martensitic transfornation heat evolved (absorbed) in single crystals of Cu-13.5 wt. % Al - 4.0 wt. % Ni alloy in the course of their in-situ calorimetric study under constrained shape memory deformation conditions. The second is a burst character of emerg-ing shape memory strain in the course of heating single crystals of Ni49Fe27Ga18CoSubscript text6 ferromagnetic alloy. The crystals were preliminary compressed along [110] crystallographic axis for the purpose of giving them a shape memory deformation. As a result of burst martensitic transition, the monocrystalline samples standing on a hard base and loaded additional weight of 400 g threw up this weight on 66 mm height .