Power law fluctuations and scale-free spatial patterns are known to characterize steady state plastic flow in crystalline materials. In this Letter we study the emergence of correlations a simple Frenkel-Kontorova-type model 2D plasticity which is largely free arbitrariness, amenable analytical study, capable generating critical exponents matching experiments. Our main observation concerns possibility reduce continuum an integer-valued automaton revealing inherent discreteness flow.

Cells modify their volume in response to changes osmotic pressure but it is usually assumed that other active shape variations do not involve significant fluctuations. Here we report experiments demonstrating water transport and out of the cell needed for formation blebs, commonly observed protrusions plasma membrane driven by cortex contraction. We develop simulate a model fluid-mediated membrane-cortex deformations show permeable necessary bleb which otherwise impaired. Taken together, our...

We show that nonlinear continuum elasticity can be effective in modeling plastic flows crystals if it is viewed as a Landau theory with an infinite number of equivalent energy wells whose configuration dictated by the symmetry group GL(2,Z). Quasistatic loading then handled athermal dynamics, while lattice-based discretization play role regularization. As proof principle, we study dislocation nucleation homogeneously sheared 2D crystal and global tensorial invariance elastic foments...

Plastic deformations in crystals produce microstructures with randomly oriented patches of unstressed lattice forming complex textures. We use a mesoscopic Landau-type tensorial model crystal plasticity to show that such textures rotations can originate from crystallographically exact microslips which self organize the form laminates pseudotwin type. The formation be viewed as an effective internal ``wrinkling'' lattice. While disguises itself elastically neutral rotation, behind it is...

We address the question of why larger, high-symmetry crystals are mostly weak, ductile, and statistically subcritical, while smaller with same symmetry strong, brittle supercritical. link it to another intermittent elasto-plastic deformation submicron features highly unusual size sensitivity scaling exponents. use a minimal integer-valued automaton model crystal plasticity show that growing variance quenched disorder, which can serve in this case as proxy for increasing size, undergo...

Shape memory alloys inherit their macroscopic properties from mesoscale microstructure originated the martensitic phase transformation. In a cubic to orthorhombic transition, single variant of martensite can have compatible (exact) interface with austenite for some special lattice parameters in contrast conventional austenite/twinned transition layer. Experimentally, compatibility results dramatic drop thermal hysteresis and gives rise very stable functional over cycling. Here, we...

We study the mechanical response of a dislocation-free 2D crystal under homogenous shear using new mesoscopic approach to plasticity, Landau-type theory, accounting for global invariance energy in space strain tensors while operating with an infinite number equivalent wells. The advantage this is that it eliminates arbitrariness dealing topological transitions involved, instance, nucleation and annihilation dislocations. use discontinuous yielding pristine micro-crystals as benchmark problem...

Recently acoustic signature of dislocation avalanches in HCP materials was found to be long tailed size and energy, suggesting critical dynamics. Even more recently, the intermittent plastic response generic for micro- nano-sized systems independently their crystallographic symmetry. These rather remarkable discoveries are reviewed this paper perspective recent studies performed our group. We discuss physical origin scaling properties fluctuations address nature dependence on crystalline...

Solid state thermodynamical reaction method involving mixing, calcinations and sintering were used to prepare a high temperature superconductor with nominal composition Bi2-xCuxPb0.3Sr2Ca2Cu3O10+δ for Cu (0 d x 0.5). The effect of time substituting on Bi sites have been investigated by X-ray diffraction, resistance measurements oxygen content obtain the optimum conditions formation stabilization TC phase (2223-phase). results showed that is 140 hr at 860 oC. Substitution equals 0.2 0.3 led...

Macroscopic properties of structural materials are strongly dependent on their microstructure. However, the modeling evolution is a complex task because mechanisms involved such as plasticity, recrystallization, and phase transformations, which common processes taking place in metallic alloys. This complexity led to growing interest atomistic simulations formulated without any auxiliary hypotheses beyond choice interatomic potential. In this context, we propose here model based an overdamped...

The work focuses on the influence of moderate plastic deformation subsequent partial recrystallization hexagonal zirconium (Zr702). In considered case, strain induced boundary migration (SIBM) is assumed to be dominating mechanism. This hypothesis analyzed and tested in detail using experimental EBSD-OIM data Monte Carlo computer simulations. An EBSD investigation performed samples, which were channel-die compressed two perpendicular directions: normal direction (ND) transverse (TD) initial...