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Much of the impact of thermal activation on the low-temperature dynamics of the thermoelastic martensitic transformation (MT) remains unresolved. This study introduces the concept of viscosity of superelasticity, referred to herein as “viscosuperelasticity,” to comprehensively interpret the slow dynamics of stress-induced isothermal MT at low temperatures. The thermal activation dynamics underlying this concept allow for deriving the time-temperature-transformation (TTT) diagrams at any holding stress from the temperature- and strainrate-dependent superelastic stress-strain curves. Experimental results for isothermal forward and reverse MTs comprehensively agree with the derived TTT diagrams, disclosing the nonreciprocity in the dynamics between the forward and reverse MT paths. One of the representative manifestations of viscosuperelasticity is the difference in the cooling/heating-rate dependence of the forward/reverse MT starting and finishing temperatures (TMs, TMf, TAs, and TAf). A significant decrease in TMs and TMf with increasing cooling rate explains kinetic arrest, and a gradual increase in TAs and TAf with increasing heating rate explains the difficulty in detecting the isothermal evolution of the reverse MT. The TTT diagrams also enable the impact of thermal activation upon dynamic cooling/heating to be evaluated quantitatively, explaining the nonergodic thermal-history dependence of anelastic transformation strain, which has been believed to be an essential signature of strain glass. The concept of viscosuperelasticity offers a comprehensive interpretation of nonreciprocal isothermal dynamics, kinetic arrest, and nonergodicity in the anelastic strain as manifestations of thermal activation of MTs.

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• In Copyright
  

  ©2023 American Physical Society

Keyword: マルテンサイト変態, 超弾性, 熱活性化, 等温変態

Date published: 2023-10-04

Publisher: American Physical Society (APS)

Journal:

• Physical Review B (ISSN: 24699969) vol. 108 issue. 13 134103

Funding:

• Kyoto University Foundation
• Japan Science and Technology Agency JPMJPR22Q6
• Japan Society for the Promotion of Science 23K04366
• Japan Society for the Promotion of Science 19H02418
• Japan Society for the Promotion of Science 19K22052

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4716

First published URL: https://doi.org/10.1103/physrevb.108.134103

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Updated at: 2024-09-02 12:30:12 +0900

Published on MDR: 2024-09-02 12:30:12 +0900