Aluminum alloys has significant application potential in the cladding and core structures of fourth- generation nuclear reactors due to their excellent thermal neutron absorption ability. Molecular dynamics

thermodynamic simulations

and corrosion experiments are employed to investigate the corrosion behavior of the cast and 3D printed AlSi10Mg alloy in a supercritical CO2 at 300℃ and 15 MPa. The results show that the segregation behavior of Mg2Si in the cast AlSi10Mg alloy leads to the formation of a discontinuous and incomplete Al2O3 oxide film on its surface

while the Al

Si and Mg elements in the 3D printed AlSi10Mg alloy are evenly distributed

forming a continuous and complete Al2O3 oxide film. CO2 molecules decompose into CO molecules and free carbon after adsorption reaction on the surface of the AlSi10Mg alloy

and some CO gas molecules are dispersed in the gas environment near the Al-rich oxide film. Since the bond length of free carbon with Al and Si is too long

a stable carbide structure can’t be formed

resulting in carbon being deposited on the surface of the Al2O3 oxide film in a free state and unable to penetrate into the oxide film and the matrix. Therefore

the corrosion resistance and carburization resistance of the 3D printed AlSi10Mg alloy in a supercritical CO2 environment are better than those of the cast AlSi10Mg alloy. The results can provide a basis for the selection of materials for the fourth-generation supercritical CO2 nuclear reactor.