On the nature of attractive dislocation crossed states

Abstract

Attractive non-coplanar dislocations that cannot react to form junctions can, nevertheless, form crossed states, i.e., junctions of null length. Such configurations have recently been described by Wickham and co-workers as an output of numerical simulations. The physical origin of the crossed states is cleared out and their conditions of occurrence are calculated within a simplified elastic frame. The results are further discussed by comparison with mesoscopic simulations of intersecting dislocations in fcc and bcc crystals. Ó

Dislocation reactions, plastic anisotropy and forest strengthening in MgO at high temperature

“…2a and b). Both intersection maps are highly comparable to the well-known LomerCottrell reaction observed in FCC crystals (Madec et al, 2002a). This similitude comes partly from the direction 1/2h1 1 0i and the amplitude of the existing dislocation Burgers vector in MgO that is closed to the FCC case.…”

“…This type of simulations depicts possible reactions between two intersecting dislocations and provides preliminary information on the strength of forest interactions between slip systems. Such type of calculations have already been made in several materials including FCC and BCC structures Madec et al, 2002a;Wickham et al, 1999), HCP structures (Capolungo, 2011;Monnet et al, 2004) and other materials like olivine (Durinck et al, 2007) and ice (Devincre, 2012). Carrez and collaborators also published a first numerical investigation of the dislocation interactions between 1/2h1 1 0i{1 1 0} slip systems in MgO (Carrez et al, 2005).…”

Dislocations and Plastic Deformation in MgO Crystals: A Review

“…Finally, the junction strength τ j scales with µb/l j (with l j the junction arm length) depending on (ϕ 1 , ϕ 2 ). Interactions maps were computed for a wide range of materials as, e.g., in fcc and bcc metals [120][121][122], hcp structures [123,124], ice [125] and minerals like olivine [126]. Figure 10, based on MgO slip system analysis, .…”

Simulation of dislocation patterns in multislip

“…The conditions for the formation and destruction of the three types of junctions between perfect dislocations in f.c.c. crystals (the Lomer, glissile and Hirth locks) have been investigated in detail as a function of the orientation of the interacting lines [8,9,17]. Fig.…”