First principles study on helium doping at the interface of Fe Cr alloy

Abstract: As the main component of low-activation ferrite/martensite steel in candidate materials for fusion reactor, Fe-Cr alloy will enter the material and produce micro-defects under actual working conditions, which will cause radiation damage and affect the radiation resistance and other physical and chemical properties of the material. In this paper, the interface of Fe-Cr alloy, which is the main material of reactor, is simulated by first-principles calculation. He atoms are doped in different gap positions and substitution positions. The formation energy is calculated after structural optimization, and the stability of He atoms in different positions is obtained. At the same time, the calculation of volume shows that the lattice aberration of He at the interstitial position of Fe octahedron near the interface is caused by the hybridization of He, Fe and Cr atoms at specific positions.