Industrial Chemistry
Open Access

Abstract

The development of high-temperature irradiation-resistant nickel-based alloys has been receiving much attention due to their potential applications in molten salt reactors (MSRs). Silicon carbide nanoparticle-reinforced nickel-based composites (Ni-SiCNP), with milling time ranged from 8 to 48h, were prepared using mechanical alloying and spark plasma sintering. In addition, unreinforced pure nickel samples were also prepared for comparative purposes. The microstructure of the Ni–SiCNP composites was characterized by TEM and their mechanical properties were investigated by tensile measurements. The TEM results showed well-dispersed SiCNP particles, either within the matrix, between twins or along grain boundaries (GB), as well as the presence of stacking faults and twin structures, characteristics of materials with low stacking fault energy. The tensile test results indicated that the addition of SiCNP can effectively strengthen the nickel. Furthermore, the helium diffusion behavior of such composites and pure nickel under 3 MeV helium ion irradiation at 600°C with ion fluence up to 3×1020 ions/m2 has also been studied. The TEM results indicated that the presence of dispersed SiCNP in nickel can inhibit the growth of helium bubbles, thereby mitigate the helium embrittlement and swelling of nickel-based alloys. The theoretical calculation results using the density functional theory (DFT) showed that the helium atoms prefer to diffuse to the interface between SiCNP and nickel matrix, and thus avoid the grain boundary segregation and also the growth of helium bubbles. This study confirmed the feasibility of dispersing carbides in nickel-based alloys to improve the irradiation-resistant performance of materials.

Biography

Email: huanghefei@sinap.ac.cn