2011 年 52 巻 7 号 p. 1369-1373
It is known that segregation of P atoms at grain boundaries (GB) enhances the intergranular embrittlement in Fe. In the present work, first-principles tensile tests have been performed on two bcc Fe cell models with a Σ3 (111)⁄[1\\bar10] tilt GB: the cell model without P segregation at the GB (clean GB model) and the cell model with P segregation at the GB (P-segregated GB model). The tensile strength and the strain to failure in the P-segregated GB model were 6% and 13% lower than those in the clean GB model. The first bond breaking occurred at the Fe-P bond due to the covalent-like characteristics, although the charge densities were high at the Fe-P bonds. This premature bond breaking of Fe-P was independent of the location of the P atom.
