TY - JOUR

T1 - Influence of preliminary straining on the recovery stress in tini shape memory alloy working element

AU - Sibirev, A. V.

AU - Belyaev, S. P.

AU - Resnina, N. N.

N1 - Publisher Copyright: © 2021, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/5

Y1 - 2021/5

N2 - The influence of the preliminary deformation (in the austenite state) of TiNi working elements on the peculiarities of the strain recovery and stress generation during thermal cycling was investigated. Experiments were carried out under the torsion mode with different values of the stiffness of the working element — counter body system. It is shown that, at low stiffness values (<8 GPa), an increase in the dislocation slip stress by preliminary plastic deformation in austenite does not lead to an increase in the recovery stress. Preliminary deformation leads to an increase in the recovery stress only at a stiffness, at which the recovery stress was close to the value of the yield stress in non-deformed samples. It was found that plastic deformation in austenite led to a decrease in the values of the recovery strain due to the suppression of the reversible strain by the plastic strain. It was shown that there are no qualitative differences in the dependences of the recovery stress and recovery strain values on stiffness obtained for samples where the shape memory effect was initiated by different ways (cooling under the constant load, deformation in martensite state or cooling in the regime of the stress relaxation).

AB - The influence of the preliminary deformation (in the austenite state) of TiNi working elements on the peculiarities of the strain recovery and stress generation during thermal cycling was investigated. Experiments were carried out under the torsion mode with different values of the stiffness of the working element — counter body system. It is shown that, at low stiffness values (<8 GPa), an increase in the dislocation slip stress by preliminary plastic deformation in austenite does not lead to an increase in the recovery stress. Preliminary deformation leads to an increase in the recovery stress only at a stiffness, at which the recovery stress was close to the value of the yield stress in non-deformed samples. It was found that plastic deformation in austenite led to a decrease in the values of the recovery strain due to the suppression of the reversible strain by the plastic strain. It was shown that there are no qualitative differences in the dependences of the recovery stress and recovery strain values on stiffness obtained for samples where the shape memory effect was initiated by different ways (cooling under the constant load, deformation in martensite state or cooling in the regime of the stress relaxation).

KW - Martensitic transformations

KW - Recovery stress

KW - Shape memory alloys

KW - Thermal cycling

KW - TiNi alloy

KW - shape memory alloys

KW - martensitic transformations

KW - thermal cycling

KW - recovery stress

UR - http://www.scopus.com/inward/record.url?scp=85107204464&partnerID=8YFLogxK

U2 - 10.22226/2410-3535-2021-2-209-212

DO - 10.22226/2410-3535-2021-2-209-212

M3 - Article

AN - SCOPUS:85107204464

VL - 11

SP - 209

EP - 212

JO - Letters on Materials

JF - Letters on Materials

SN - 2218-5046

IS - 2

ER -