Emergence of Disclination and Cooperative Deformation at the Intersection of Kink Interface and Slip Deformation

Abstract

In order to clarify a strengthening principle due to the presence of the kink band, the geometry of the intersection of slip deformation and kink interface was analyzed in a situation where there is only one slip system and no cracking or delamination occurs. When the kink interface is penetrated by slip deformation while maintaining the continuity of deformation, disclinations are always formed at the intersection, and the migration of kink interface is required (cooperative deformation). The disclination and the cooperative deformation always increase the stress for deformation, regardless of how small the penetrating slip is. In layered structures such as long-period stacking ordered (LPSO) Mg alloys, there is a mismatch in the number of layers at the intersection of the kink interface and the slip deformation, which necessitates cutting of the layers. This means that the 〈c〉-dislocation is necessary for the cooperative deformation in LPSO-Mg. It is suggested that when the Peierls stress of 〈c〉-dislocation is much higher than that of basal slip (easy slip), the presence of kink interface leads to a dramatic increase in the stress for plastic deformation.