|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Fatigue in Materials: Fundamentals, Multiscale Modeling and Prevention
||Grain Size Effects on Fatigue Crack Growth in Nanocrystalline NiTi
||William LePage, Aslan Ahadi, Q.P. Sun, John Shaw, Samantha Daly
|On-Site Speaker (Planned)
This talk discusses the effects of grain size on the fatigue crack growth of superelastic NiTi shape memory alloy with average grain size ranging from 10 to 1500 nm, which was investigated through the use of multiscale experimental techniques. Crack initiation and growth rates were characterized with optical digital image correlation (DIC), and then fatigue properties were elucidated on the microscale with in-situ, distortion-corrected SEM-DIC. High-magnification SEM micrographs were captured during crack growth in compact tension samples patterned for SEM-DIC by self-assembled nanoparticle deposition for sub-micron-scale displacement resolution. Crack opening and closure displacements in the crack wake were computed to quantify the effect of martensitic phase transformation as an energy-dissipating mechanism during crack propagation. Displacement fields from SEM-DIC also enabled assessing models of phase transformation strain fields at the crack tip. The enhanced resolution of SEM-DIC overcomes challenges that others have encountered for crack-tip and crack-closure measurements in nanocrystalline alloys.
||Planned: Stand-alone book in which only your symposium’s papers would appear (indicate title in comments section below)