Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni Alloy
Severe plastic deformation via high-ratio differential speed rolling (HRDSR) was applied to the Ni-rich Ti-50.8Ni alloy. Application of HRDSR and a short annealing time of 5 min at 873 K leads to the production of a partially recrystallized microstructure with a small grain size of 5.1 μm. During th...
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MDPI AG
2022-11-01
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| Online Access: | https://www.mdpi.com/1996-1944/15/21/7822 |
| _version_ | 1797467393567490048 |
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| author | Tae-Jin Lee Woo-Jin Kim |
| author_facet | Tae-Jin Lee Woo-Jin Kim |
| author_sort | Tae-Jin Lee |
| collection | DOAJ |
| description | Severe plastic deformation via high-ratio differential speed rolling (HRDSR) was applied to the Ni-rich Ti-50.8Ni alloy. Application of HRDSR and a short annealing time of 5 min at 873 K leads to the production of a partially recrystallized microstructure with a small grain size of 5.1 μm. During the aging process for the annealed HRDSR sample at 523 K for 16 h, a high density of Ni<sub>3</sub>Ti<sub>4</sub> particles was uniformly precipitated over the matrix, resulting in the formation of an <i>R</i> phase as the major phase at room temperature. The aged HRDSR sample exhibits excellent superelasticity and superelastic cyclability. This achievement can be attributed to an increase in strength through effective grain refinement and particle strengthening by Ni<sub>3</sub>Ti<sub>4</sub> and a decrease in the critical stress for stress-induced martensite (B19′) due to the presence of the <i>R</i>-phase instead of B2 as a major phase at room temperature. The currently proposed method for using HRDSR and post-deformation heat treatment allows for the production of Ni-rich NiTi alloys with excellent superelasticity in sheet form. |
| first_indexed | 2024-03-09T18:53:01Z |
| format | Article |
| id | doaj.art-88e9e902a02f4ce29880dbec70ce7553 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-09T18:53:01Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
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| spelling | doaj.art-88e9e902a02f4ce29880dbec70ce75532023-11-24T05:41:25ZengMDPI AGMaterials1996-19442022-11-011521782210.3390/ma15217822Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni AlloyTae-Jin Lee0Woo-Jin Kim1Department of Materials Science and Engineering, Hongik University, Mapo-gu, Sangsu-dong 72-1, Seoul 121-791, KoreaDepartment of Materials Science and Engineering, Hongik University, Mapo-gu, Sangsu-dong 72-1, Seoul 121-791, KoreaSevere plastic deformation via high-ratio differential speed rolling (HRDSR) was applied to the Ni-rich Ti-50.8Ni alloy. Application of HRDSR and a short annealing time of 5 min at 873 K leads to the production of a partially recrystallized microstructure with a small grain size of 5.1 μm. During the aging process for the annealed HRDSR sample at 523 K for 16 h, a high density of Ni<sub>3</sub>Ti<sub>4</sub> particles was uniformly precipitated over the matrix, resulting in the formation of an <i>R</i> phase as the major phase at room temperature. The aged HRDSR sample exhibits excellent superelasticity and superelastic cyclability. This achievement can be attributed to an increase in strength through effective grain refinement and particle strengthening by Ni<sub>3</sub>Ti<sub>4</sub> and a decrease in the critical stress for stress-induced martensite (B19′) due to the presence of the <i>R</i>-phase instead of B2 as a major phase at room temperature. The currently proposed method for using HRDSR and post-deformation heat treatment allows for the production of Ni-rich NiTi alloys with excellent superelasticity in sheet form.https://www.mdpi.com/1996-1944/15/21/7822shape memorysuperelasticityagingsevere plastic deformationgrain refinementsuperelastic cyclability |
| spellingShingle | Tae-Jin Lee Woo-Jin Kim Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni Alloy Materials shape memory superelasticity aging severe plastic deformation grain refinement superelastic cyclability |
| title | Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni Alloy |
| title_full | Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni Alloy |
| title_fullStr | Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni Alloy |
| title_full_unstemmed | Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni Alloy |
| title_short | Effect of Severe Plastic Deformation and Post-Deformation Heat Treatment on the Microstructure and Superelastic Properties of Ti-50.8 at.% Ni Alloy |
| title_sort | effect of severe plastic deformation and post deformation heat treatment on the microstructure and superelastic properties of ti 50 8 at ni alloy |
| topic | shape memory superelasticity aging severe plastic deformation grain refinement superelastic cyclability |
| url | https://www.mdpi.com/1996-1944/15/21/7822 |
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