Effects of transition metals on the grain boundary cohesion in tungsten

The cohesion effect of transition metals on W grain boundaries (GBs) was studied via first-principles calculations. Systematic d-band filling for a given atomic environment results in trends of cleavage energy as a function of the solute's electronic valence across different GB sites. Various solutes were found to strengthen the GB. Furthermore, lower- and higher-valence elements enhance cohesion at different positions. This suggests that employing both lower-valence (Hf, Ta, Nb) and higher-valence solutes (Re, Os, Ru) may further increase intergranular cohesion.