Magnetic-field-induced transformation and strain in polycrystalline FeMnGa ferromagnetic shape memory alloys with high cold-workability

Poor mechanical properties severely impede the practical application of ferromagnetic shape memory alloys. In this Letter, we report cold deformation-induced B2-γ phase transformation in polycrystalline FeMnGa alloys. Due to this property, the alloy achieved a high strength of ∼1000 MPa and a ductility of ∼75% in a compressive test, and a 90% deformation in thickness in a cold rolling experiment, indicating excellent cold-workability. The recrystallization annealing transformed the cold rolled γ phase to a textured B2 phase, which exhibited magnetic-field-induced phase transformation and anisotropic transformation strains. These properties indicate that FeMnGa is a promising candidate for future applications in actuator devices.