Effect of Zr doping on precipitated phase and mechanical properties of NiFeGa alloy

Abstract

Abstract The effect of Zr alloying on the precipitates and mechanical properties of magnetic shape memory alloy Ni55Fe12Ga34-xZrx (x=0,2,3,4,5,12 atomic number fraction, the same below) was investigated. The results showed that Ni54Fe12Ga34 alloy is a single martensitic phase with high brittleness. Ni55Fe12Ga34-xZrx (x=2, 3, 4, 5) alloy was composed of γ phase and eutectic structure. The compressive strength of Ni55Fe12Ga34-xZrx alloy increases with the increase of Zr content, which is caused by the precipitation of the second phase and eutectic structure. When Zr content was 12 at.%, the alloy consists of γ phase, eutectic structure and strip phase. Due to the appearance of strip brittle phase, the compression strength of the alloy decreases. With the increase of Zr content, the strip phase increases, and the compression strength decreases gradually. Ni55Fe12Ga34-xZrx series alloys have excellent superelasticity, and the alloy has the best superelasticity when Zr content is 5 at.%.