Effect of Annealing Temperature on Microstructure and Corrosion Properties of Co₃₅Ni₃₅Al₃₀ Ferromagnetic Shape Memory Alloy

The Co₃₅Ni₃₅Al₃₀ ferromagnetic shape memory alloy was prepared by non-consumable vacuum melting furnace, and the alloy was annealed. The effects of annealing temperature on the microstructure and shape recovery characteristics of Co₃₅Ni₃₅Al₃₀ alloy were analyzed by metallographic microscopy and X-ray diffractometer. The effect of annealing temperature on the corrosion resistance of the alloy was analyzed by electrochemical test. The results show that with the increase of annealing temperature, the shape memory effect of the alloy increased first and then decreased, and the microstructure of the alloy was gradually refined. When the annealing temperature was 1 200, 1 300 ℃, the shape memory effect of the alloy was almost the same, but when the annealing temperature was 1 200 ℃, the strength of the alloy was higher. With the increase of annealing temperature, the corrosion resistance of the alloy increased first and then decreased. At 1 200 ℃, the corrosion current density of the alloy was the smallest, the self-corrosion potential was relatively high, the corrosion rate was the smallest, the polarization resistance was relatively larg, and the corrosion resistance of the alloy was the best.