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

摘要

Two new phenomena recently revealed and studied by the authors in the well-known shape memory alloys, such as Cu-AI-Ni and Ni-Fe-Ga, are described. The first is the strong decrease in the martensitic transformation heat released (absorbed) in single crystals of the Cu-13.5 wt. % Al - 4.0 wt. % Ni alloy in the course of their in-situ calorimetric study under constrained shape memory deformation. The second is the burst emergence of a shape memory strain at heating of single crystals of the Ni_(49)Fe_(27)Ga_(18)Co_6 ferromagnetic alloy. The crystals were preliminary compressed along the [110] crystallographic axis to impart a shape memory deformation. As a result of a burst martensitic transition, single crystal samples mounted on a hard base and loaded by an additional weight of 400 g throw up this weight to a height of 66 mm.