Structural modifications of boron carbide irradiated by swift heavy

Boron carbide (B4C) behavior under irradiation is widely studied in order to predict the lifetime of this material in future (Generation IV) nuclear fission reactors. This paper is focused on the effects of high electronic stopping powers (Se) on B4C structure modifications. Sintered B4C samples were irradiated at room temperature with swif(t) heavy ions (between 0.5 and 3 MeV.u(- 1)) corresponding to Se values in the 4.1 to 15.4 keV.nm(-1) range at the sample surface. In order to investigate the structural changes as a function of depth, transmission electron microscopy and Raman mapping were performed on the irradiated samples along the path of the incident ions. For the highest Se values, damage results in the creation of large hillocks at the sample surface along with the amorphization of the bulk. These results are explained, in the frame of the inelastic thermal spike model, by local melting in latent tracks that are created only when irradiations are performed above a Se threshold evaluated at around 9 keV nm(-1). (C) 2020 Elsevier B.V. All rights reserved.