EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Inter-granular failure of nickel (Ni) single grain boundaries (GBs) due to the segregation of sulfur (S), hydrogen (H) and their co-segregation has been investigated by means of Density Functional Theory (DFT) calculations and micro cantilever bending test. The results of DFT calculations have been used in a McLean-isotherm-based thermokinetic model to estimate S and H content at a representative GB and to evaluate its resistance to brittle failure. Later on, theoretical results have been used to interpret the results of in-situ electrochemically charged micromechanical tests of Ni bi-crystals with and without S. Theoretical findings and experimental observations have been put together to interpret a possible mechanism of Ni bi-crystal fracture in the presence of H and S.