First-Principles Calculations of Hydrogen Trapping Energy on Incoherent Interfaces of Aluminum Alloys

Abstract

We attempted to calculate the hydrogen trapping energies at the incoherent interfaces of MgZn₂ precipitates and Mg₂Si crystallites in aluminum alloys from first-principles calculations. Since the unit cell containing the incoherent interface does not satisfy the periodic boundary condition, resulting in a discontinuity of crystal blocks, the hydrogen trapping energy was calculated in a region far from the discontinuity (vacuum) region. We found considerable trapping energies for hydrogen atoms at the incoherent interfaces consisting of assumed atomistic arrangement. We also conducted preliminary calculations of the reduction in the cohesive energy by hydrogen trapping on the incoherent interfaces of Mg₂Si in the aluminum matrix.