On the plastic deformation of a CoCrFeNiW-C alloy at elevated temperatures: Part I. Serrated plastic flow and its latent dynamics

Multi-component Co-alloys are a class of promising metallic materials for high-temperature applications. The present work primarily focuses on the plastic deformation mechanisms of a CoCrFeNiW-C alloy at 650 °C, with emphases on dislocation slip intermittency and plastic flow features. To this end, by integrating in situ scanning electron microscopy-based tests, statistical analyses, and theoretical calculations, several mechanistic insights are revealed. In this material, the plastic flow is featured by evident serration events with a self-organized critical dynamic feature, where mixed Type A and B serrations operate at a moderate deformation level, followed by the onset of a higher magnitude Type B serration. As temperature increases up to 700 and 750 °C, although more evident Type C serration occurs, the self-organized criticality along with the spatial-temporal power-law scaling relation remains nearly unaffected. Microstructural relevance of the serration mechanisms and the deformation substructural characteristics are also explored in greater depth.