First-principles study on the effects of co-segregation of Ti, B and O on the cohesion of the alpha-Fe grain boundary

摘要

The effects of Ti, B and 0 co-segregating on the alpha-Fe Sigma 5 [001]/(010) grain boundary are studied by a first-principles method, DMol. We found that (Ti + B) acts as an enhancer, but 0 can completely offset the beneficial effect of Ti. Based on the segregation energy analysis, it is also found that Ti can effectively prohibit O from segregating to the grain boundary and therefore eliminate the embrittlement of grain boundary induced by O. Thus, Ti is a kind of desirable addition in alpha-Fe to improve the mechanical properties.