Evaluation of novel Ti-doped 3D carbon–carbon composites under transient thermal loads

Abstract

3D Ti-doped and undoped carbon–carbon composites (CFCs) were exposed to transient thermal loads to simulate plasma disruptions, in the electron beam test facility JUDITH at different power densities and multiple shots in order to study the evolution in the behavior of the material. The thermal shock response of the undoped and Ti-doped materials was compared in order to study the influence of titanium carbide as dopant. The erosion itself is driven during the first shots by macroscopic erosion (brittle destruction), which is a result of thermally induced stresses. With increasing number of shots, no more brittle destruction is observed and the main erosion mechanism is sublimation due to local overheating. This is also confirmed by the decrease of the erosion rate with increasing the number of shots. The pitch fibers are hardly affected by the applied heat loads and they show almost no erosion, especially in the Ti-doped composite.