Decoupling Mechanical and Chemical Effects on Energetics of Coherent Nanoprecipitates with Interfacial Segregation

Abstract

Recent research on aluminum alloys targets enhancing high-temperature strength through coherent interface design and interfacial segregation, making accurate interfacial energetics calculations essential. While these calculations are well-established in pristine systems, the introduction of foreign atoms in doped systems introduces a combination of mechanical and chemical effects within the bulk phases, making it challenging to accurately assess interfacial energetics. Our study tackles this challenge using a Density Functional Theory (DFT) framework, accurately quantifying energy variations from interfacial and coherency strain energies, as well as additional energy contributions from chemical and mechanical interactions with foreign solute atoms. Our findings underscore the critical role that mechanical lattice stress exerted by solute atoms plays in the energetics of interfacial segregation within 7000 series aluminum alloys, uncovering a unique stabilization mechanism that sets them apart from the 2000 series. This has profound implications for selecting solutes to enhance interfacial segregation and aluminum alloy stabilization.

Keywords: 7000 series aluminum alloys, interfacial segregation, nanoprecipitates, interfacial energetics, Density Functional Theory (DFT) calculations.