Effect of β- and γ′-phase particles on the shape memory effect and superelasticity in [001]-oriented FeNiCoAlTi single crystals

The paper presents data on the effect of ageing at 873 K (two-step and one-step) of [0 0 1]-oriented FeNiCoAlTi single crystals on the precipitate of gamma'- and beta-phase particles, M-s temperature, superelasticity and shape memory effect. It has been shown that in two-step ageing at 873 K, the gamma'- and beta-phase particles are precipitated; in one-step ageing, only the gamma'-phase particles are precipitated. Precipitation of beta-phase particles increase M-s temperature by 72-100 K compared with one-step ageing. Plasticity, superelasticity and shape memory effect in crystals with beta-phase are determined by the ageing time in the second step. When ageing at the second step for 2 h, superelasticity and shape memory effect are 3% and 4.5%, respectively, and after 4 h of ageing, the crystals become brittle. (C) 2019 Elsevier B.V. All rights reserved.