Effects of solution treatment on microstructure and superelasticity of FeNiCoAlTaB alloy

The effects of solution treatment on the microstructure, macrotexture and superelastic properties of FeNiCoAlTaB alloy were investigated in this study. The results showed that rolling texture of (011) [2-11] (Brass-type) developed by cold-rolling with reduction of 98.5% transferred to (023) [100] and (032) [100] texture after solution treatment with the temperature above 1200 °C, forming a strong 〈100〉 fiber recrystallization texture. Solution treatments at the temperature above 1250 °C facilitated the formation of a single austenite phase which was in favor of the precipitation of γ ′ phase during aging treatment and martensitic transformation in cyclic tension. In addition, microcracks appeared readily in the alloy for solution treatment with the temperature above 1300 °C, which negatively affected the superelastic performance. Under the experimental conditions of this study, the 98.5% cold-rolled FeNiCoAlTaB alloy acquired a preferable superelasticity after solution treatment at 1250 °C for 1 h and aging treatment at 600 °C for 72 h, with the total tensile strain of 3.8%, the complete cyclic superelastic strain of 1.6% and the tensile strength of 885 MPa.