Invited: Mechanical changes in nanomaterials due to ion induced effects

BRINGA, EDUARDO

Lille

Congreso; e-mrs; 2016

Generation and evolution of radiation-induced defects have been studied with atomistic simulations for decades. However, the role of such defects in the changing mechanical properties of materials under irradiation is often unclear at the nanoscale. For instance, irradiation of low dimensional materials, in particular graphene, can lead to large changes in mechanical properties. A detailed study of the interplay of defects and nanoindentation has been carried out, including the role of pre-strain in the samples [1]. Nanofoams have been shown to be radiation-resistant [2,3] and radiation-induced defects can change their mechanical properties, as probed by simulated nanoindentation or tension/compression testing. It is difficult to model realistic foam filaments of tens of nm, but nano pillars could be considered a basic building block for foams, and their simulation can help understanding possible effects at these scales [4]. Nanocrystals have also been proposed as radiation resistant materials, but it was recently shown that, in the electronic energy-loss regime, nanodiamond can actually be more sensitive to irradiation than single-crystal diamond [5], and mechanical properties change due to the presence of resulting sp2 rich inclusions. Nanocrystals indeed can absorb radiation products, and indeed grain boundaries can absorb large quantities of hydrogen [6], which then changes mechanical properties for both fcc and bcc metals. [1] J. Martinez, C. Ruestes, E.M. Bringa, M.J. Caturla, to be submitted.[2] E.M. Bringa et al., Nanoletters 12, 3351 (2012).[3] C. Anders, E.M. Bringa, H.M. Urbassek, NIMB 342, 234 (2015).[4] E. Figueroa et al., JNM 467, 677 (2015).[5] F. Valencia et al., Carbon 93, 458 (2015). [6] P. Piaggi et al., JNM 458, 233 (2015).