|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Advanced Thermo-mechanical Characterization of Materials with Special Emphasis on In Situ Techniques
||Influence of Dislocation Density and Grain Boundaries on the Scaling Behaviour of Ultrafine-grained BCC Micropillars
||Reinhard Fritz, Alexander Leitner, Verena Maier-Kiener, Daniel Kiener
|On-Site Speaker (Planned)
While size effects in micron-sized single crystalline (sxx) specimens are well investigated, controversial results have been reported for miniaturized ultrafine-grained (ufg) specimens in literature. In this work, two different bcc metals, Cr and W, with different critical temperatures and thus varying scaling exponents were investigated. Sxx as well as ufg pillars with sample sizes ranging from 0.2 to 4 Ám were tested performing in-situ SEM microcompression tests at room and elevated temperatures, whereby for ufg pillars a novel, interesting strength scaling exponent was observed. Furthermore, the dislocation density was also varied within these ufg samples by using an in-situ heating technique to recover the highly distorted microstructures. Within this presentation, we will shed more light into the governing deformation mechanisms and finally we will demonstrate whether grain boundaries or dislocation density are responsible for the occurring scaling behaviour in the ufg micropillars.
||Planned: Supplemental Proceedings volume