# US 2014/0207228 A1 · Shape memory alloy articles with improved fatigue performance and methods therefore > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0207228 A1 - Document ID: US20140207228A1 - Status: Published application - Kind: A1 - Application number: 14/226,503 - Filed: 2014-03-26 - Published: 2014-07-24 - Earliest claimed: 2003-05-02 - Assignees: W. L. Gore & Associates, Inc. - Applicants: W. L. Gore & Associates, Inc. - Inventors: Bret A. Dooley; Christopher C. Lasley; Michael R. Mitchell; Robert R. Steele; Eric M. Tittelbaugh - Web page: https://patentgrep.com/patent/US20140207228A1 ## CPC - A61F 2/82: Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents (stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07) - A61L 31/022: {Metals or alloys} - A61L 31/121: {having an inorganic matrix} - A61L 31/14: Materials characterised by their function or physical properties {, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials} - C22F 1/006: {Resulting in heat recoverable alloys with a memory effect} - A61B 2017/00867: {shape memory effect} - A61C 2201/007: using shape memory effect - A61L 2400/16: Materials with shape-memory or superelastic properties - A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C) - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00) ## Abstract 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. ## Claims ### Claim 1 A self-expanding implantable medical device comprising a frame including nitinol that exhibits superelastic behavior at body temperature, the frame of said self-expanding implantable medical device being expandable from a constrained delivery profile to an expanded operative profile, wherein the frame is pre-strained by the application of a pre-straining bending force to an extent that selectively induces at least about 8.0% tensile strain at or near only a surface of at least one selected location on the frame during circumferential compaction of the frame to a smaller size, wherein following release of the pre-straining force, the frame circumferentially expands to, or near to, its geometry prior to the application of the pre-straining forces. ### Claim 2 (depends on 1) A self-expanding implantable medical device according to claim 1 wherein the pre-straining results in at least about 8.5% tensile strain. ### Claim 3 (depends on 2) A self-expanding implantable medical device according to claim 2 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 4 (depends on 1) A self-expanding implantable medical device according to claim 1 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 5 A self-expanding implantable medical device comprising a frame including nitinol that exhibits superelastic behavior at body temperature, the frame of said self-expanding implantable medical device being expandable from a constrained delivery profile to an expanded operative profile, wherein the frame is pre-strained by the application of a pre-straining torsional force to an extent that selectively induces at least about 8.0% tensile strain at or near only a surface of at least one selected location on the frame during circumferential compaction of the frame to a smaller size, wherein following release of the pre-straining force, the frame circumferentially expands to, or near to, its geometry prior to the application of the pre-straining forces. ### Claim 6 (depends on 5) A self-expanding implantable medical device according to claim 5 wherein the pre-straining results in at least about 8.5% tensile strain. ### Claim 7 (depends on 6) A self-expanding implantable medical device according to claim 6 wherein the pre-straining torsional force is applied in a controlled manner. ### Claim 8 (depends on 5) A self-expanding implantable medical device according to claim 5 wherein the pre-straining torsional force is applied in a controlled manner. ### Claim 9 A self-expanding implantable medical device comprising a frame including nitinol that exhibits superelastic behavior at body temperature, the frame of said self-expanding implantable medical device being expandable from a constrained delivery profile to an expanded operative profile, wherein the frame is pre-strained by the application of a pre-straining bending force to an extent that selectively induces at least about 0.40% non-recoverable tensile strain at or near only a surface of at least one selected location on the frame during circumferential compaction of the frame to a smaller size, wherein following release of the pre-straining force, the frame circumferentially expands to, or near to, its geometry prior to the application of the pre-straining force. ### Claim 10 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 11 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining results in at least about 0.45% non-recoverable tensile strain. ### Claim 12 (depends on 11) A self-expanding implantable medical device according to claim 11 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 13 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining results in at least about 0.50% non-recoverable tensile strain. ### Claim 14 (depends on 13) A self-expanding implantable medical device according to claim 13 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 15 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining results in at least about 0.60% non-recoverable tensile strain. ### Claim 16 (depends on 15) A self-expanding implantable medical device according to claim 15 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 17 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining results in at least about 0.80% non-recoverable tensile strain. ### Claim 18 (depends on 17) A self-expanding implantable medical device according to claim 17 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 19 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining results in at least about 1.0% non-recoverable tensile strain. ### Claim 20 (depends on 19) A self-expanding implantable medical device according to claim 19 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 21 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining results in at least about 1.5% non-recoverable tensile strain. ### Claim 22 (depends on 21) A self-expanding implantable medical device according to claim 21 wherein the pre-straining bending force is applied in a controlled manner. ### Claim 23 (depends on 9) A self-expanding implantable medical device according to claim 9 wherein the pre-straining results in at least about 2.0% non-recoverable tensile strain. ### Claim 24 (depends on 23) A self-expanding implantable medical device according to claim 23 wherein the pre-straining bending force is applied in a controlled manner.