Modeling of the grain boundary segregation of helium in α-Fe

We proposed a kinetic theory model of helium segregation from the bulk to the grain boundary in α-Fe. This model is constructed on the basis of the ab initio results of large segregation energy and large deduction in strength at the grain boundary due to helium. The simulation results of the model showed the typical segregation features as function of bulk concentration of helium and temperature in general agreement with experiment. In addition, the results are compared with McLean’s model for monoatomic-layered grain boundary segregation in equilibrium, and the validity of this equilibrium model is discussed.