INVESTIGATION OF ATOMIC-SCALE ENERGETICS ON LIQUID METAL EMBRITTLEMENT OF ALUMINUM DUE TO GALLIUM

M Rajagopalan and MA Bhatia and KN Solanki and MA Tschopp, TMS 2014 SUPPLEMENTAL PROCEEDINGS, 1069-1076 (2014).

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 Sigma 3(111) and Sigma 11(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.

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