Abstract: Nanostructured materials with abundant defect sinks show good radiation tolerance due to their efficient absorption of irradiation-induced interstitials and vacancies. However, the poor thermal stability and limited size of such nanomaterials severely limit their practical applications. Herein, we report a novel flexible free-standing network-structured hybrid consisting of amorphous carbon encapsulated nickel nanocrystals anchored on a single-wall carbon nanotube scaffold with excellent radiation tolerance up to 5 dpa at 673 K and exceptional thermal stability up to 1073 K. The nano-scale Ni-SWCNT network with abundant Ni-SWCNT interfaces and grain boundaries provides effective sinks and fast transportation channels for defects, which effectively absorb irradiation-induced defects and improved the irradiation tolerance. Furthermore, the formation of a low-energy Ni-C interface and surface thermal grooves significantly reduces the system free energy and increased thermal stability. The amorphous carbon layer produces an external compressive radial stress that inhibits Ni grain boundaries from migrating, which greatly improves the thermal stability of the hybrid by pinning GBs at grooves between grains and facilitates the annihilation of irradiation-induced defects at the sinks. This work provides a new strategy to improve the thermal stability and radiation tolerance of nano-materials used in an irradiation environment.

Key words: Radiation tolerance, Ni nanocrystals, Carbon nanotube, Thermal stability, Flexible hybrid