K. Niitsu
(National Institute for Materials Science)
;
Y. Yano
;
R. Kainuma
;
H. Inui
説明:
(abstract)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.
権利情報:
©2023 American Physical Society
キーワード: マルテンサイト変態, 超弾性, 熱活性化, 等温変態
刊行年月日: 2023-10-04
出版者: American Physical Society (APS)
掲載誌:
研究助成金:
原稿種別: 著者最終稿 (Accepted manuscript)
MDR DOI: https://doi.org/10.48505/nims.4716
公開URL: https://doi.org/10.1103/physrevb.108.134103
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更新時刻: 2024-09-02 12:30:12 +0900
MDRでの公開時刻: 2024-09-02 12:30:12 +0900
| ファイル名 | サイズ | |||
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IsothermalMart_34.pdf
(サムネイル)
application/pdf |
サイズ | 3.32MB | 詳細 |