Investigation of atomic-scale energetics on liquid metal embrittlement of aluminum due to gallium

In this work, the role of atomistic-scale energetics on liquid-metal embrittlement of aluminum (Al) due to gallium (Ga) was explored. Ab-initio and molecular mechanics were employed to probe the formation energies of vacancies and segregation energies of Ga for <100>, <110> and <111> symmetric tilt grain boundaries (STGBs) in Al. Results show that site-to-site variation of formation and segregation energies within the boundary are substantial, with the majority of sites having lower energies than the bulk values. Moreover, a few GBs such as Σ3(111) and Σ11(113) of different tilt axes with relatively high segregation energies (between 0 and -0.1 eV) at the boundary were also found, providing a new atomistic perspective in the GB engineering of material with smart GB networks to mitigate or control LME and more general embrittlement phenomena in alloys.