Nature of phosphorus embrittlement of the FeΣ3[11¯0](111) grain boundary
Abstract
Thermodynamic, electronic, and magnetic properties of the P/FeΣ3[11¯0](111) grain boundary and the P/Fe(111) free surface are compared using the full potential linearized augmented plane-wave method. The calculated segregation-energy difference of 0.8 eV is consistent with the embrittling effect of P according to the Rice-Wang thermodynamic model. The clean FeΣ3[11¯0](111) boundary is found to undergo an ω phase transition which results in an antiferromagnetic coupling within the core of the grain boundary. Structural relaxations in the grain boundary alter the P segregation energy by ~2.0 eV and are found to play an important role in defining the correct sign and value of the segregation energy difference controlling embrittlement. The P/Fe chemical interaction is found to be ``embeddedlike'' electrostatic rather than covalent in both environments. Long-range effects of P impurities are found for the Fe magnetization which reduce the embrittling potency of P.
- Publication:
-
Physical Review B
- Pub Date:
- July 1994
- DOI:
- 10.1103/PhysRevB.50.75
- Bibcode:
- 1994PhRvB..50...75W
- Keywords:
-
- 61.72.Mm;
- 81.40.Np;
- 73.20.Hb;
- 75.30.Hx;
- Grain and twin boundaries;
- Fatigue corrosion fatigue embrittlement cracking fracture and failure;
- Impurity and defect levels;
- energy states of adsorbed species;
- Magnetic impurity interactions