Ni-Co-Ga OR Co-Ni-Ga HEUSLER-TYPE MAGNETIC SHAPE MEMORY ALLOY AND MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a magnetic shape memory alloy capable of causing magnetic-field-induced martensitic phase transformation attendant on the application of external magnetic energy and capable of showing giant magnetostriction. SOLUTION: In the Heusler-type Ni-Co-Ga or Co-Ni-Ga magnetic shape memory alloy, high crystal anisotropy is provided and high-frequency low-energy grain boundary is formed and martensitic phase transformation is induced by magnetic fields. Rapidly solidified foil of this alloy exhibits excellent bending ductility at a bending ductility test, and particularly, those having a composition ratio of Ni2 CoGa or Co2 NiGa are free from rupture even at 180 deg. bending angle. Accordingly, the problem of brittleness existing in Ni2 MnGa alloys can be solved.