|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Biological Materials Science Symposium
||Monotonic and Cyclic Response of Austenitic and Martensitic NiTi wires for Medical Device Applications
||Elizabeth Gurin, Yiyi Yang, Hyunmin Kim, K. Sharvan Kumar
|On-Site Speaker (Planned)
NiTi shape memory alloys are commonly used in stents and other implantable medical devices. This study examines the cyclic stress-strain response of ~400 μm diameter NiTi wires, initially both in the austenitic state and in the martensitic state. Stress-controlled tension-tension tests were conducted and S-N curves were obtained for R=0.3; the resulting fracture surfaces were analyzed in the SEM. Additionally, monotonic tensile tests were performed on the various fatigued specimens of the initially austenitic wire, and changes in response relative to the tensile response of the initial state were noted. To understand the role of the stress-induced austenite-martensite transformation on cyclic life, stress ranges below the super-elastic plateau, above the plateau, and across the plateau were examined by varying maximum stress and the R ratio. Strain-controlled tests are being performed to further examine the consequence of the “reversible” transformation on fatigue life. These results will be presented and discussed.
||Planned: Publication Outside of TMS (Indicate publication title and publisher if known.)