The effects of interaction geometry on pinning strength induced by interstitial dislocation loop in BCC-Fe

Irradiation induced dislocation loops in Fe-based alloys can cause material hardening by impeding the mobility of dislocation. Using molecular dynamics (MD), the interaction between 1 / 2 1 1 1 > { 1 1 ¯ 0 } edge dislocation (ED) and 1/2 interstitial dislocation loops with Burgers vector (BV) along different directions in BCC (body centered cubic)-Fe were investigated, and the influence of interaction geometry (means the relative position between dislocation glide plane (GP) and loop equator plane) on the CRSS (critical resolved shear stress) for dislocation to move again induced by loops was analyzed. It was found that the pinning strength of 1/2 loop was estimated to be 0.2–0.8, varying with the BVs direction of loops and the interaction geometries. The present study clearly showed that when parameterizing the dislocation dynamics, more interaction geometries should be considered in order to get a more quantitative pinning strength.