Grain Boundary Segregation of Substitutional Solutes/Impurities and Grain Boundary Decohesion in BCC Fe

The segregation of certain impurities to grain boundaries (GBs) which induced by neutron irradiation in Reactor Pressure Vessel (RPV) steels may have adverse effects upon their mechanical properties. In this work, ten symmetrical <110> and <001> tilt GBs in BCC Fe were created based on Coincident Site Lattice method, the GBs segregation embrittling potency was simulated by adding phosphorus, copper, nickel, and manganese to the boundaries and free surface (FS) using molecular static method. We have addressed both high- and low-angle tilt grain boundaries. Systematic Molecular Statics simulations were performed employing recent Embedded Atom Method (EAM) potentials. We show that P will strongly bind to GBs and FS; P and Cu have a detrimental effect on the GB cohesion, and segregation of these two elements will lead to GB embrittlement.