Experimental quantification of dynamic processes in micrometer-sized single-crystalline W

Dynamic transition processes of defects within microstructures govern most of the mechanical deformation behaviour in materials. However, quantifying them remains challenging, especially within microscopic volumes. In this work, dynamic frequency sweep experiments on micrometer-sized cantilevers fabricated by focused ion beam milling from single-crystalline W are presented as a model material system for microstructural defect quantification. The resulting mechanical spectra show the indenter-inherent resonance peak as well as auxiliary features, which cannot be explained by external structural relaxations in the load train. Using a classical Arrhenius-type framework, activation volumes ranging from 0.26 to 1.89 b 3 have been found for these features and compared with density functional theory calculations. The results suggest that the observed features correspond most likely to microstructural defects, with experimental values in a reasonable order-of-magnitude, underlining the possibility to measure such fundamental processes also within microscopic features.