Superelasticity and fatigue in oligocrystalline shape memory alloy microwires
In oligocrystalline shape memory alloys, the total grain boundary area is smaller than the surface area of the specimen, leading to significant effects of free surfaces on the martensitic transformation and related shape memory and superelastic properties. Here we study sample size effects upon the...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Elsevier
2016
|
| Online Access: | http://hdl.handle.net/1721.1/102372 https://orcid.org/0000-0001-9856-2682 |
| _version_ | 1826193958218235904 |
|---|---|
| author | Ueland, Stian M. Schuh, Christopher A. |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Ueland, Stian M. Schuh, Christopher A. |
| author_sort | Ueland, Stian M. |
| collection | MIT |
| description | In oligocrystalline shape memory alloys, the total grain boundary area is smaller than the surface area of the specimen, leading to significant effects of free surfaces on the martensitic transformation and related shape memory and superelastic properties. Here we study sample size effects upon the superelastic characteristics of oligocrystalline microwires after one loading cycle and after many. Cu–Zn–Al wires with diameters ranging from ∼100 down to ∼20 μm are fabricated by the Taylor liquid processing technique and characterized through both uniaxial cyclic tensile testing and mechanically constrained thermal cycling. The energy dissipated per superelastic cycle increases with decreasing wire diameter, and this size effect is preserved after extensive cycling despite a significant transient evolution of the superelastic response for early cycles. We also present fatigue and fracture data, indicating that oligocrystalline wires of this normally brittle alloy can exhibit fatigue lifetimes two orders of magnitude improved over conventional polycrystalline Cu–Zn–Al. |
| first_indexed | 2024-09-23T09:47:57Z |
| format | Article |
| id | mit-1721.1/102372 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T09:47:57Z |
| publishDate | 2016 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | mit-1721.1/1023722022-09-26T13:49:35Z Superelasticity and fatigue in oligocrystalline shape memory alloy microwires Ueland, Stian M. Schuh, Christopher A. Massachusetts Institute of Technology. Department of Materials Science and Engineering Schuh, Christopher A. Ueland, Stian M. Schuh, Christopher A. In oligocrystalline shape memory alloys, the total grain boundary area is smaller than the surface area of the specimen, leading to significant effects of free surfaces on the martensitic transformation and related shape memory and superelastic properties. Here we study sample size effects upon the superelastic characteristics of oligocrystalline microwires after one loading cycle and after many. Cu–Zn–Al wires with diameters ranging from ∼100 down to ∼20 μm are fabricated by the Taylor liquid processing technique and characterized through both uniaxial cyclic tensile testing and mechanically constrained thermal cycling. The energy dissipated per superelastic cycle increases with decreasing wire diameter, and this size effect is preserved after extensive cycling despite a significant transient evolution of the superelastic response for early cycles. We also present fatigue and fracture data, indicating that oligocrystalline wires of this normally brittle alloy can exhibit fatigue lifetimes two orders of magnitude improved over conventional polycrystalline Cu–Zn–Al. Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies 2016-05-03T13:15:51Z 2016-05-03T13:15:51Z 2011-10 2011-09 Article http://purl.org/eprint/type/JournalArticle 13596454 1873-2453 http://hdl.handle.net/1721.1/102372 Ueland, Stian M., and Christopher A. Schuh. “Superelasticity and Fatigue in Oligocrystalline Shape Memory Alloy Microwires.” Acta Materialia 60, no. 1 (January 2012): 282–292. https://orcid.org/0000-0001-9856-2682 en_US http://dx.doi.org/10.1016/j.actamat.2011.09.054 Acta Materialia Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf Elsevier Prof. Schuh via Angie Locknar |
| spellingShingle | Ueland, Stian M. Schuh, Christopher A. Superelasticity and fatigue in oligocrystalline shape memory alloy microwires |
| title | Superelasticity and fatigue in oligocrystalline shape memory alloy microwires |
| title_full | Superelasticity and fatigue in oligocrystalline shape memory alloy microwires |
| title_fullStr | Superelasticity and fatigue in oligocrystalline shape memory alloy microwires |
| title_full_unstemmed | Superelasticity and fatigue in oligocrystalline shape memory alloy microwires |
| title_short | Superelasticity and fatigue in oligocrystalline shape memory alloy microwires |
| title_sort | superelasticity and fatigue in oligocrystalline shape memory alloy microwires |
| url | http://hdl.handle.net/1721.1/102372 https://orcid.org/0000-0001-9856-2682 |
| work_keys_str_mv | AT uelandstianm superelasticityandfatigueinoligocrystallineshapememoryalloymicrowires AT schuhchristophera superelasticityandfatigueinoligocrystallineshapememoryalloymicrowires |