Thermoelastic martensitic transformation and superelasticity in Fe–Ni–Co–Al–Nb–B polycrystalline alloy

The effects of the addition of Nb and B on grain boundary precipitation, martensitic transformation and superelasticity were investigated in the Fe–Ni–Co–Al alloys. The addition of Nb increases the hardness and the martensitic transformation changes from non-thermoelastic to thermoelastic, while the addition of B is effective for suppressing the formation of brittle grain boundary precipitates. By the recrystallization texture developed by 98.5% cold-rolling and annealing, high ductility and superelasticity with 5% recoverable strain were realized in the Fe–28Ni–17Co–10.5Al–2.5Nb–0.05B polycrystalline alloy.