Aluminum-doped U3Si2 composite fuels with enhanced oxidation resistance

Al-doped U3Si2 composite fuels with controlled microstructure were fabricated by spark plasma sintering that display greatly-improved oxidation resistance as compared with monolithic and Al-doped silicides prepared by standard powder metallurgy or arc melting. The effects of Al additives on the thermalmechanical properties and oxidation resisance of the micron- and nano-sized U3Si2 composites were investigated. A minimal addition of 1.8 at% Al is effective to increase the onset oxidation temperature of as-fabricated U3Si2 pellets to 580 degrees C, which can be further increased to 610 degrees C by thermal annealing. The Al-doped U3Si2 composite fuels also display simultaneously higher hardness and fracture toughness than un-doped U3Si2. These results highlight an effective strategy by integrating minimal Al additives, microstructure control and post-thermal annealing to design advanced silicide fuels with excellent oxidation resistance, desired thermal-mechanical properties and maintained high fissile element density. (c) 2020 Elsevier B.V. All rights reserved.

Automated summary

Al-doped U3Si2 composite fuels with controlled microstructure displayed greatly improved oxidation resistance and thermal-mechanical properties. Minimal addition of Al effectively increased the onset oxidation temperature and thermal annealing further enhanced it. Additionally, the Al-doped composite fuels exhibited higher hardness and fracture toughness compared to undoped U3Si2.