Influence of quenching rate on the magnetic and martensitic properties of Ni–Fe–Ga melt-spun ribbons

We have fabricated Ni–Fe–Ga β single phase alloy ribbons with Ga content less than 25 at. %. Higher spinning rate of melt-spinning technique can produce β single phase alloys without precipitation of γ particles, whereas lower spinning rate results in the β+γ two phase structure. This higher quenching rate is found to be able to fully suppress the formation of γ phase during fabrication. The martensitic and magnetic transition temperatures of β phase ribbons are both above room temperature, and the ribbon show saturation magnetization as high as 56.5 emu/g at room temperature. These features are attractive for practical applications. The effects of quenching rate on microstructure, martensitic transformation, and magnetic properties are discussed.