Experimental evaluation of the Peierls stresses in a variety of crystals and their relation to the crystal structure

Dislocation Structure and Mobility in Hcp Rare-Gas Solids: Quantum versus Classical

“…Our results reveal a strong tendency towards dislocation dissociation into Shockley partials separated by wide regions of fcc-like stacking fault, in analogy to what occurs in solid helium. We find that the Peierls stress for the glide of edge dislocations in the hcp basal plane amounts to ∼1 MPa, which is very similar in magnitude to the values reported for classical metals with the hcp structure (e.g., Zr and Cd) [12,13]. However, in contrast to other classical solids but in analogy to solid helium, edge dislocations in hcp rare gases turn out to be extremely mobile: they can diffuse with an approximate velocity of 50 m/s in the absence of any applied stress at temperatures as low as 25 K (that is, well below the corresponding Debye temperature Θ D ∼ 65 K [16]).…”

“…This result is orders of magnitude smaller than the τ P values reported for archetypal crystals with cubic symmetry (e.g., Fe and Mo) [13]; however, to our surprise, it is very similar in magnitude to the Peierls stresses found in classical metals with the hcp structure (e.g., Zr, Cd, and Mg) [12,13]. Very recently, Landinez-Borda et al have shown in solid helium that τ P nominally amounts to zero, that is, dislocations can move freely throughout the crystal in the absence of thermal excitations and shear stresses [11].…”

“…For instance, Landinez-Borda et al have shown that in solid helium either screw or edge dislocations with Burgers vectors contained in the hcp basal plane tend to dissociate into Shockley partial dislocations separated by ribbons of fcc-like stacking fault [11]. The same behavior is observed in classical metals with the hcp structure like, for instance, Zr [2,12,13]. Nevertheless, since the nature of the atomic interactions in rare gases and metallic systems are so different, the physical origins of such similarities (or the differences explained above) are not totally understood.…”

Dislocations and Plastic Deformation in MgO Crystals: A Review

“…The further propagation of the kinks along the dislocation line is responsible for the glide of the whole dislocation. The theoretical description of dislocation motion involving the kink-pair mechanism was successfully applied to the understanding of elemental deformation processes (see, for instance, [81]) in several materials, including bcc metals [82][83][84][85][86][87][88][89], covalent materials such as silicon [90][91][92] and ionic materials [93][94][95], including MgO [23].…”

A self-consistent plasticity theory for modeling the thermo-mechanical properties of irradiated FCC metallic polycrystals

“…For FCC metals, the initial lattice resistance is always pretty small at room temperature, e.g. τ 0 of copper or silver is only a few MPa (Kamimura et al, 2013). Thus, the initial lattice resistance for FCC crystals is often neglected in the numerical analysis.…”