Thermal- and stress-induced martensitic transformations in 001-oriented Ni_(44)Fe_(19)Ga_(27)Co_(10) single crystals

摘要

The microstructures and martensitic transformations upon cooling/heating, and under a compressive load have been studied for 001-oriented Ni44Fe19Ga27Co10 (at.) single crystals after growth and following annealing at 1448 K for 1 h, followed by quenching. Heat treatment determined the microstructure of the high-temperature phase (crystal lattice, the presence of gamma-phase particles, and the formation of B2-phase nanodomains). A wide superelasticity temperature range of 277 K was found. Annealing led to an 80 K increase in the martensitic transformations temperatures, widening of transformations intervals, and an increase in the strength properties of the high-temperature phase by 100 MPa, which led to a shift of the superelasticity range towards high temperature.