Revealing the Al/L12-Al3Zr inter-facial properties: Insights from first-principles calculations

To uncover the mechanical performance and micro-structure of Al/L1(2)-Al3Zr interface through density functional theory, four interface models are investigated considering two different terminations of L1(2)-Al3Zr surfaces along the [001] direction. Results indicated stacking sequence and atom type between two phases influences the mechanical performance of the interface quite well. The interface consisting of four Al atom-terminated Al(001) slab as well as one Al and four Zr atom-terminated L1(2)-Al3Zr(001) slab not only has relatively even charge distribution due to the same atomic arrangement as L1(2)-Al3Zr bulk, but also enjoys the strong hybrid bonds between inter-facial Al and Zr atoms, gaining the best performer in the tensile test. However, it's the different situation for the model constructed by four Al-terminated Al(001) slab and four Al-terminated L1(2)-Al3Zr(001) slab, the poorest performer. As for the other two interface models with the similar fracture energy and peak stress, one of them, though held together just through the relatively weak bonds of inter-facial Al, has the advantage of evenly-located inter-facial atoms which results in the even charge distribution, for the same atomic arrangement as Al bulk. The other, the inter-facial atoms of which are distributed unevenly, gets the benefit of the strong hybridization of inter-facial atoms.