Extended defects or imperfections in metals and alloys describe the state of the microstructure at different length and time scales. Many material properties and processing routes inherently influence or are affected by the microstructure and its extended defects. The spatial arrangement of these defects imposes various critical dimensions at multiple length scales and thereby gives rise to size effects. These can, in turn, be utilized to archive otherwise unprecedented materials performance in nanostructured materials.

At the nanoscale or the level of the defect core, the local chemistry and direct defect-defect interaction also opens a rich materials design space, which can be explored and exploited, for example, for extreme conditions or thermomechanical stability. A prominent example is plasticity taking place in High Entropy Alloys, with is affected by pronounced local chemical fluctuations influencing the defect properties.

This symposium will explore the fundamental properties of extended defects (e.g., solid-state interfaces, dislocations, grain boundaries, …) in the context of the interplay between defect structure and chemistry. Their role in determining the behavior of metallic materials will be addressed, and potential avenues to tailor materials by defect engineering are identified. The symposium will emphasize simulations that bridge length and time-scales, as well as corresponding experiments providing highly local structural and chemical information in the vicinity of the defects.

alloy defects diffusion dislocations fatigue fracture grain boundaries metal microstructure strength