First-principle study on the effects of hydrogen in combination with alloy solutes on local mechanical properties of steels

The first-principle calculation method has been utilized to study the effects of hydrogen in combination with alloy elements on the mechanical properties of iron-based super-cells, with the aim to bring new insight in the design of hydrogen-resistant steels. It is found that hydrogen prefers the second and third tetrahedral interstitial sites of the alloy solutes. Nb/Zr/Mo/W/Al alloyed super-cells dropped the most in the bulk modulus by hydrogen addition. Ni/Nb/Cu/Co/Zr dropped the most in the shear modulus/Young's modulus/hardness. The underlying influencing mechanisms on the elastic mechanical properties are discussed in perspective of atomic parameters/density of states/charge density/difference charge density/Bader charge analysis.