Slip-free multiplication and complexity of dislocation networks in FCC metals

During plastic deformation of crystalline solids, intricate networks of dislocation lines form and evolve. To capture dislocation density evolution, prominent theories of crystal plasticity assume that 1) multiplication is driven by slip in active slip systems and 2) pair-wise slip system interactions dominate network evolution. In this work, we analyze a massive database of over 100 discrete dislocation dynamics simulations (with cross-slip suppressed), and our findings bring both of these assumptions into question. We demonstrate that dislocation multiplication is commonly observed on slip systems with no applied stress and no plastic strain rate, a phenomenon we refer to as slip-free multiplication. We show that while the formation of glissile junctions provides one mechanism for slip-free multiplication, additional mechanisms which account for the influence of coplanar interactions are needed to fully explain the observations. Unlike glissile junction formation which results from a binary reaction between a pair of slip systems, these new multiplication mechanisms require higher order reactions that lead to complex network configurations. While these complex configurations have not been given much attention previously, they account for about 50% of the line intersections in our database.

Irreversibility analysis in dissipative magnetohydromagnetic flow of non-Newtonian nanomaterials

The theme of this article is to scrutinize the entropy rate in hydromagnetic flow of Reiner–Philippoff nanofluid by a stretching surface. Energy equation is developed through first law of thermodynamic with dissipation and Joule heating. Furthermore, random and thermophoretic motion is discussed. Additionally, binary reaction is discussed. Physical feature of irreversibility analysis is discussed. Nonlinear expression is obtained by suitable transformation. The obtained systems are solved through the numerical method (bvp4c). Variation of entropy rate, thermal field, velocity profile, and concentration against sundry variables are discussed. Computational outcomes of thermal and mass transport rate for influential parameters are studied in tabularized form. A reverse effect holds for thermal field and velocity through magnetic variable. Higher Bingham number leads to a rise in velocity field. An intensification in thermal field and concentration is noted for thermophoretic variable. An enhancement in fluid variable leads to augments velocity. An increment in entropy analysis is seen for magnetic effect. Larger estimation of diffusion variable improves entropy rate. A reduction in concentration is noticed for reaction variable.

Binary reaction ingrained high current density and long cycle life novel anode material for lithium ion battery

The uniqueness in the physical and electrochemical properties and the structural integrity towards lithium ion storage make carbon nanotubes (CNT) a viable anode material for the lithium ion battery.