Irradiation Damage in Ti_3(Si,Al)C_2: a TEM Investigation

摘要

Ti_3SiC_2, belonging to MAX phases, is a potential candidate material, which could be incorporated in core components of future gas-cooled fast nuclear reactors (GFR). Despite extensive work on mechanical behavior, corrosion resistance, or electrical properties, data concerning the evolution of Ti_3SiC_2 under irradiation are very limited. In this work, Ti_3(Si,Al)C2 was irradiated at room temperature with 92 MeV Xe ions to induce irradiation damage. The samples were investigated by transmission electron microscopy (TEM) through front view and cross-section observations, which allowed to follow microstructure changes from 0.02 dpa up to 6.67 dpa. Progressive atomic disorder versus dose was highlighted, leading to extinction of some diffraction spots (at 0.15 dpa) and then diffuse patterns (at 3 dpa). The ABABACAC periodicity related to 3-1-2 MAX phases was lost but the image fringes of basal plans could still be identified and no amorphous ring occurred. This means that Ti_3(Si,Al)C2 was strongly affected by irradiation but did not turn to amorphous even at 6.67 dpa. This important result was correlated to previous conclusions from X-ray diffraction and nano-indentation analysis and suggests the good behavior of Ti_3(Si,Al)C_2 under irradiation in the target temperature range assigned to GFR.