Formation Mechanism of Dislocation Walls during Cyclic Deformation in an Fe–Si Alloy

Abstract

Low–cycle fatigue tests of a polycrystalline Fe–3 mass%Si alloy were performed at room temperature under a constant total strain amplitude of 1 × 10^-2. Dislocation structures were observed by high–voltage scanning transmission electron microscopy. The development of dislocation walls parallel to (110) started during the first few tens cycles of fatigue. The activation of a set of double slip systems, (211)[111] and (112)[111], contributed to the formation of (110) walls. The (110) walls lie in the directions bisecting the angles between the Burgers vectors of the two active dislocations of the double slip systems.