Reduction of preferential erosion of carbon fibre composites under intense transient heat pulses

Abstract

Two fusion-relevant carbon fibre composites (CFCs), NB31 (3D) and DMS704 (2D), have been thermally exposed in five different orientations to simulate transient events ( disruptions and ELMs). In these experiments with intense transient heat pulses in the electron beam JUDITH and the ion beam facility RHEPP-1, CFCs showed a preferential erosion of the fibre bundles aligned in the surface-plane. This phenomenon also occurred when these fibre bundles were the ones with the highest thermal conductivity. First results show that reduction of the number of fibres aligned parallel to the surface-plane strongly contributes to limiting the preferential erosion by fibre segment ejection ( brittle destruction) in CFCs. Strong mechanical attachment is essential to avoid fibre segment ejection during disruption. The selection of an optimum material orientation of the available CFCs is of relevant importance and will be further investigated.