We demonstrate direct evidence that a single-crystal-like aragonite platelet is essentially assembled with aragonite nanoparticles. The aragonite nanoparticles are readily oriented and assembled into pseudo-single-crystal aragonite platelets via screw dislocation and amorphous aggregation, which are two dominant mediating mechanisms between nanoparticles during biomineralization. These findings...

The migration of dislocations affects many material properties including deformation, plasticity and electronic properties. In order to understand the mechanism of the motion of dislocations, both experimental and theoretical studies have been performed [1]. It is known that full dislocations such as edge or screw dislocations can dissociate into Shockley partial dislocations, which have higher...

Dislocation slip is investigated in a metastable  titanium alloy with the Ti-23Nb-0.7Ta-2Zr0.4Si composition (at. %) by in situ straining experiments in a transmission electron microscope (TEM). Moving dislocations have a/2<111> Burgers vectors and glide in {110}, {112} or {123} planes. The mobility of screw dislocations is lowered by punctual defects and the existence of a stable and sessile ...

In this paper, the dynamics of a system of a finite number of screw dislocations is studied. Under the assumption of antiplane linear elasticity, the two– dimensional dynamics is determined by the renormalised energy. The interaction of one dislocation with the boundary and of two dislocations of opposite Burgers moduli are analysed in detail and estimates on the collision times are obtained. S...

We present a variational framework for studying screw dislocations subject to antiplane shear. Using a classical model developed by Cermelli & Gurtin [5], methods of Calculus of Variations are exploited to prove existence of solutions, and to derive a useful expression of the Peach-Köhler forces acting on a system of dislocation. This provides a setting for studying the dynamics of the dislocat...