|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Ultrafine Grained Materials IX
||Microstructural Instabilities in Cyclically Loaded ufg Metals
||Marlene Kapp, Oliver Renk, Martin Bärnthaler, Bo Yang, Reinhard Pippan
|On-Site Speaker (Planned)
Due to their fine scaled microstructure, HPT processed ulltrafine-grained metals show an exceptional performance under high cycle fatigue. However, one challenge is their high fraction of grain boundaries leading to grain coarsening at larger strain amplitudes. Details to this coarsening remain yet unclear. To gain a thorough understanding of the coarsening process (e.g. if certain crystallographic orientations grow preferentially) cyclic micro-bending experiments were carried out quasi in-situ inside a SEM. Additional EBSD scans on the bending beams make it possible to study grain coarsening with special focus on the crystallographic orientation or the grain boundary type. Accompanying experiments on bulk samples subjected to cyclic HPT reveal a softening as a consequence of the coarsened structure in the absence of cyclic damage. Beside this direct insights into the mechanical instability of the ufg strucutre, possible driving forces for the coarsening will be the center of discussion.