Method of making shape memory alloy articles with improved fatigue performance
US8177927B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 2010 |
| Grant date | May 15, 2012 |
| Priority date | — |
| Expiry date | Aug 31, 2030 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61L2400/16
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A method of making articles made of shape memory alloys having improved fatigue performance and to methods of treating articles formed from shape memory alloy materials by pre-straining the articles (or desired portions of the articles) in a controlled manner so that the resultant articles exhibit improved fatigue performance. The shape memory articles are preferably medical devices, more preferably implantable medical devices. They are most preferably devices of nitinol shape memory alloy, most particularly that is superelastic at normal body temperature. The pre-straining method of the present invention as performed on such articles includes the controlled introduction of non-recoverable tensile strains greater than about 0.20% at the surface of a desired portion of a shape memory alloy article. Controlled pre-straining operations are performed on the shape-set nitinol metal to achieve non-recoverable tensile strain greater than about 0.20% at or near the surface of selected regions in the nitinol metal article. The pre-straining operations result in a significant increase in fatigue life of the selectively treated regions and an overall improvement in the fatigue performance of …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.