Abstract
Fe-Si alloy is well known as the material which has higher strength than pure iron and generally used as high tensile strength steel. In the Fe-Si alloy. Si solute atom affects its strength. However, this mechanism has not been clarified in detail yet. In bcc crystal, plasticity is dominated by behavior of screw dislocation and screw dislocation in bcc metal glides through the thermal activation process called double kink nucleation and kink migration. In order to research the effect of Si on strength of Fe-Si alloy, we estimate the influence of Si solute on screw dislocation behavior by determining the energy barrier for double kink nucleation and migration using atomic scale simulation. We also estimate the critical resolved shear stress (CRSS), which is one of the mechanical properties to measure the mechanical strength of materials, from the analysis of kink migration process and then discuss the relation between CRSS and Si solute concentration for understanding the strengthening mechanism of Fe-Si alloy.
