Abstract
A first principles calculation method was used to investigate the site preference of Co, Ru, W, Ta at the '/ interface in Ni-based single-crystal superalloys. The calculation results show that the addition of Co, Ru, W and Ta can decrease the total energy and the binding energy of '/ interface, which may result in an improved microstructure stability of Ni-based single-crystal superalloys. Cr atom prefers to occupy a Ni site in phase, while Ru, W and Ta atoms prefer to occupy Al sites in ' phase. It is found that the electronic bonding mechanism of '/ interface with the doped alloying elements can be summarized as the combination of d-d hybridization between Co-3d, d-p hybridization among Ru-4d, W-5d, Ta-5d orbits located at Al4 site in ' phase and Al-3p orbits and the electron charge transfers from Cr, Ru, W and Ta to Ni sites. The enhanced chemical bondings between alloying atoms and their neighbor host atoms are considered to be the main strengthening mechanism of the alloying elements in '/ interface of Ni-based single-crystal superalloys.
Published Version
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