Microstructural and thermo-mechanical characterization of carbon/carbon composites

Since advanced carbon fiber composites for fusion applications, i.e., NB31, its upgraded version NB41 and DMS780, are anisotropic in terms of thermal and mechanical properties, their response under fusion-relevant transient heat loads is highly dependent on the orientation of the material. To understand and predict the material behavior, microstructural investigations as well as tensile tests and thermal conductivity measurements were performed in different directions (along and off the three orthotropic fiber-reinforcement axis). Furthermore, ITER-like disruption loads were applied, in the electron-beam facility JUDITH, on various carbon based materials and their thermal shock response, in terms of weight loss, was compared. Under repeated disruptions, the response of the studied materials is becoming worst if oriented differently than in the direction of highest thermal conductivity and it leads towards more homogeneous but deeper erosion zones with increased tilting angle.