Stability, mechanical and surface properties for hydride of intermetallic L12-Al3Zr

Recent experiments proposed that the precipitated second-phase particles, such as L12-Al3Zr and S phase (Al2CuMg) in Al–Zn–Mg–Cu–Zr alloy, can efficiently trap enrichment H atoms, possibly weakening the H-induced damage of corresponding Al alloy. However, the change of mechanical properties of these precipitates with trapped H atom could not be explored experimentally. Here, taking intermetallic L12-Al3Zr as example, we performed a theoretical prediction to investigate the effect of trapped H on the mechanical properties of L12-Al3Zr. The results showed that although Al3ZrH compound with H located the at the geometric center is energetic and elastic stable, the lattice parameter of L12-Al3Zr seems to be expanded. The permeated H contributes to improve the hardness, brittleness and elastic anisotropy of L12-Al3Zr. In addition, we used a special method to obtain the numerical value of each (100) non-stoichiometric surface for both L12-Al3Zr and Al3ZrH compounds, providing a valuable supplement in calculating the surface energy of the non-stoichiometric surface for cubic structure.