Molecular static simulations were carried out to study the fracture process of various <110> tilt grain boundaries: Σ19{331}, Σ9{221}, Σ3{111}, Σ3{112}, Σ11{113} and Σ9{114}. The main goal of this work was to investigate variation of the deformation mechanism and fracture stress in the presence of Cr precipitates, voids and He bubbles at the core of the grain boundaries. The corresponding deformation process was characterized in terms of stress–strain relationship and deformation mechanisms were inspected by visualization tools. Based on the obtained stress–strain curves, the studied grain boundaries could be sub-divided into two types, those that exhibited extensive slip and those that do not show slip at all. The presence of Cr precipitates at the grain boundary core increased critical shear stress necessary to initiate the slip, and nucleation of a crack was regularly seen to occur at the precipitate–matrix interface. The effect of voids and He bubbles on the fracture stress was much stronger. It was revealed that the plastic deformation was essentially suppressed. The reason for the suppression was attributed to the emission of the dislocations from voids/bubbles and their pile up.

Effect of Cr precipitates and He Bubbles on the Strength of <110> Tilt Grain Boundaries in BCC Fe: an Atomistic Study. D.Terentyev, X.He: Computational Materials Science, 2011, 50[3], 925-33