Interactions between glide dislocations in a double pile-up in α-iron

Abstract

The equilibrium distribution of arrested glide dislocations on two intersecting slip planes in α-iron is computed taking into account the elastic anisotropy. From the equilibrium distribution of dislocations calculation is made of the stresses near the tip of the double pile-up (that is, a pile-up on each of two intersecting slip planes). For fifty dislocations the shear stress at the tip of a double pile-up is calculated to be 1360 σ 0, where σ 0 is the applied stress in the slip plane. This stress is greater by a factor of 27 than the tip stress of a single pile-up of the same size. The high stress concentration at the tip of a double pile-up indicates, as suggested by Cottrell, that such a dislocation arrangement could lead to initiation of cleavage cracks in α-iron.