Elemental segregation inhibits hydrogen embrittlement in aluminium alloys

Abstract

In this study, we performed first-principles calculations to determine the effects of four metallic solutes (Y, Zr, Mg, and Zn) on the hydrogen embrittlement (HE) of aluminum alloys with the Σ5(210) grain boundary (GB). The segregation energy, associated segregation concentration, and binding energy of these solutes were examined to identify their states. Moreover, the ability of the aforementioned solutes to inhibit or promote HE in the aforementioned alloys through GB energy, free surface energy, and adhesion was investigated. The Griffith and Rice–Wang–Scheiber models were used to determine the effect of nonequilibrium concentration on adhesion. Tensile tests were performed using the uniaxial strain loading method to determine the ultimate tensile strength and GB elongation of the considered alloys. The mechanism of HE inhibition by the four solutes was investigated by examining the charge density, Bader charge, and crystal orbital Hamiltonian population of the alloys. Finally, the calculation results of this study were validated through experiments.

Keywords

• Hydrogen embrittlement
• Grain boundary
• Segregation mechanism
• Strength and ductility
• Adhesion