Progress in research on strain glass transition in Ni-Ti based alloys
Equiatomic Ni-Ti alloys have been widely applied in biomedical and industrial fields，because of their shape memory effect and superelasticity originating from thermos-elastic martensitic transformation. The theoretical and experimental studies in recent years indicated that when doping sufficient am...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Journal of Aeronautical Materials
2025-02-01
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| Series: | Journal of Aeronautical Materials |
| Subjects: | |
| Online Access: | http://jam.biam.ac.cn/article/doi/10.11868/j.issn.1005-5053.2024.000152 |
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| Summary: | Equiatomic Ni-Ti alloys have been widely applied in biomedical and industrial fields，because of their shape memory effect and superelasticity originating from thermos-elastic martensitic transformation. The theoretical and experimental studies in recent years indicated that when doping sufficient amounts of defects (excess solute atoms，foreign alloying dopants， dislocations and nanosized precipitates) into equiatomic Ni-Ti alloys，the resistance from such defects could suppress the first-order martensitic transformation and achieve strain glass transition with the formation of randomly short-range ordered nanodomains. The strain glass transition is characterized by some typical features such as invariant macroscopic structure，broken ergodicity，frequency dependence of dynamic mechanical properties and high damping capacity. In spite of no first order martensitic transformation occurred during cooling, strain glass can exhibit unique shape memory effect and superelasticity because of the stress loading induced transformation from strain glass to martensite and the reversed transformation by stress unloading. The superelasticity of strain glass alloys are closely related to the type and concentration of defects. The strain glasses with moderate concentration of defects exhibit the superelastic behavior similar to conventional Ni-Ti based alloys. By contrast，under temperature or/and stress fields the strain glass ↔ R transition could occur in the strain glasses with high concentration of defects，leading to the superelasticity with small recovery strain and slim hysteresis over a broad temperature range. Strain glass transition could be achieved in Ni-Ti alloys by deformation to introduce large number of dislocations. If only the evolution of nanodomains is involved and no B19′ martensite forms in the Ni-Ti strain glass under external stress，the alloy could perform large linear superelasticity with slim hysteresis. The underlying mechanism for such superelastic behavior lies in that under stress the evolution of nanodomains does not need nucleation，and the energy loss for nucleation can be avoided. In the present paper，the proposition, novel properties and the research progress of the strain glass transition in Ni-Ti based alloys were reviewed. The principle for designing Ni-Ti based alloys with superelasticity in wide temperature range and their applications in engineering are briefly introduced. |
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| ISSN: | 1005-5053 |