A computational study of the carburization phenomena in a Fe?Ni alloy

S. SIMONETTI; L MORO; G BRIZUELA; A. JUAN

JOURNAL OF PHYSICS - D (APPLIED PHYSICS)

Institute of Physics

Lugar: London; Año: 2008 vol. 41 p. 125006 - 125013

0022-3727

Massive carburization can occur in metallic service components due to operating conditions. The changes in the microstructure result in severe embrittlement of the material leading to a loss of corrosion resistance. In this paper, a first step in the study of the electronic structure and bonding that occur during carburization phenomena has been performed. The interaction between a carbon atom and a Fe50Ni50 alloy containing a vacancy has been studied by ASED-MO cluster calculations, firstly in a vacancy region and then on the FeNi(1 1 1) surface. The minimum energy position for the C atom in the vacancy region was found to be at 1.19Å from the vacancy centre. The addition of a C atom in the FeNi matrix containing a vacancy decreases the strength of the local Fe?Fe bond to about 80% of its original bulk value. This bond weakening is mainly a consequence of the C?Fe interaction. On the other hand, the minimum energy position of the C atom on the FeNi(1 1 1) was found to be at 1.60Å from the surface. The principal interaction is again C?Fe. The C-surface bonding is achieved mainly at the expense of the weakening of the Fe?Ni nearest neighbours bond to C, which decreases to about 52%.