Smart 3D Network Nanocomposites Collect Irradiation-Induced “Trash”

Developing outstanding radiation-resistant materials with excellent thermal and mechanical properties and self-healing ability remains a great challenge for advanced nuclear energy systems. Here, we incorporate three-dimensional (3D) carbon nanotube (CNT) networks into iron nanocrystals (Fe NCs) to obtain functional bulk Fe-CNT nanocomposites, exhibiting much higher thermal conductivity and mechanical properties than the Fe NCs without sacrificing strength. Irradiations by energetic helium (He) and krypton ions show that 3D CNT networks act as gigantic-capacity “nano-dustbins” to collect and store He atoms and defects via a “loading-transporting-unloading” mechanism in the grain boundary-CNT (GB-CNT) configuration, thus greatly enhancing their radiation tolerance compared with the Fe NC counterparts. The energetic landscape of interactions of He/defects with the GBs and the Fe-CNT interfaces in the nanocomposites are revealed by first-principles calculations. This work offers a promising strategy for material design of high-performance structural materials for future advanced nuclear reactors.