A study was made of aspects of iron embrittlement in a face-centered cubic lattice with a vacancy in the presence of hydrogen as an impurity. The energy calculations were performed using the atom superposition and electron delocalization method. The electronic structures were analyzed by using the extended Hückel molecular orbital package. It was found that the H in bulk face-centered cubic iron prefers octahedral sites while in the presence of a vacancy it was located near the defect in a position shifted from the center of the hole. The formed Fe–H bond makes the Fe–Fe bonds first neighbours to the vacancy 28% weaker with respect to the H-free structure.

Comparative Study of H-Atom Location, Electronic and Chemical Bonding in Ideal and Vacancy Containing-FCC Iron. D.R.Saravia, A.Juan, G.Brizuela, S.Simonetti: International Journal of Hydrogen Energy, 2009, 34[19], 8302-7