The role of various heterostructures on radiation tolerance of Cu-based nanocomposites

Abstract

Using heterogeneous or multilayer structures of graphene and molybdenum disulfide (MoS2) has bright prospects for designing NCs with high radiation tolerance. This heterostructure can improve the radiation tolerance of Cu-based nanocomposites (NCs). In this study, the effects of the morphology of interface materials on the radiation tolerance of NCs are investigated. Single cascade induced by 3, 6, and 9 keV primary knocked-on atom (PKA) and 6 keV PKA-induced cascade overlaps are studied in three different NCs using molecular dynamics (MD) simulations. Results show the performance of interface morphology to inhibit defects in bulk regions of NCs. A comparison between radiation tolerance and stability of the Cu-based NCs including MoS2/gr/MoS2 heterostructure (Sample 1), Cu/5gr/Cu (Sample 2), and Cu/MoS2@Cu@MoS2/Cu (Sample3) shows that Cu-MoS2-gr configuration has the lower number of surviving defects after single cascade induced by different energies of PKA. This phenomenon highlights the bonds’ role of S-S, Mo-Mo, and Mo-S of the MoS2 and ultra-strength C-C bonds of graphene in controlling the frequent collision-triggered shock wave’s energy in layers of the Cu-MoS2-gr interface. We found that with increasing the number of cascade overlaps, the number of defects in the cascade bulk (bulkc) region of Sample 2 and Sample 3 NCs fluctuates. Results show that after about fifth overlapped cascades, the raising rate of the number of defects in the sub-cascade bulk (bulksc) region of the Sample 3 NC is higher than that of other NCs. These results prove that the damaged area which has been created by the first collision cascade, doesn’t change with increasing the number of overlapped cascades, but can affect controlling defects in bulks. Results imply that the composite resulting from Cu-MoS2-gr and Cu-gr exhibits an extraordinary ability to resist irradiation damage. These results highlight the role of interface morphology in inhibiting damage and suggest new models of NCs.