Plastic deformation of materials occurs by the motion of defects known as dislocations and disclinations. High-resolution transmission electron microscopy was used to directly reveal the individual dislocations that constitute partial disclination dipoles in nanocrystalline, body-centered cubic iron that had undergone severe plastic deformation by mechanical milling. The mechanisms by which the...

We report in situ electron microscopy observations of the plastic deformation of individual nanometer-sized Au, Pt, W, and Mo crystals. Specifically designed graphitic cages that contract under electron irradiation are used as nanoscopic deformation cells. The correlation with atomistic simulations shows that the observed slow plastic deformation is due to dislocation activity. Our results also...

This work is a primary achievement in studying the CO2 and N2–oil systems. To predict gas-liquid relative permeability curves, a Shan-Chen type multicomponent multiphase lattice Boltzmann model for two-phase flow through 2D porous media is developed. Periodic and bounce back boundary conditions are applied to the model with the Guo scheme for the external body force (i.e., the pressure gradient...

The early Cenozoic topography of the northern Tibetan plateau remains enigmatic because paucity independent paleoelevation constraints. Long-held views northward propagating deformation imply a low Paleogene elevation, but this prediction is speculative. We apply flexural modeling to reconstructed isopach data obtained from Qaidam basin, which requires larger topographic load in Qilian Shan and...

It is generally known that severe plastic deformation processes with back pressure not only apply higher hydrostatic stress and more deformation compared to what a regular process can apply to a workpiece but also prevent surface defects in the workpiece during the process. Hydrostatic cyclic expansion extrusion (HCEE) was developed recently for processing long ultrafine-grained metals and allo...

In this study, polycarbonate (PC) and polystyrene (PS) are subjected to plastic deformation by means of cold rolling and the resulting variation of the free volume and its subsequent time evolution after rolling is investigated by means of positron annihilation lifetime spectroscopy (PALS). The value of the long lifetime component that is attributed to the decay of ortho-positronium (tau(o-Ps))...

in this paper to predict the critical conditions for onset of elastic-plastic wrinkling of flange of a two-layered circular blank during the deep-drawing process a closed-form semi-analytical elastic-plastic solution using tresca yield criterion alongwith deformation theory in plasticity with considernig the perfectly plastic behaviour of materials is presented. simplifying the presented soluti...