Molecular dynamics simulations are performed to study the atomistic mechanisms governing the pseudoelasticity and shape memory in nickel–titanium (NiTi) nanostructures. For a h110i – oriented nanopillar subjected to compressive loading–unloading, we observe either a pseudoelastic or shape memory response, depending on the applied strain and temperature that control the reversibility of phase tr...

We review unique mechanisms of plastic deformation in nanoand micropillars. At the nanoscale, it is shown that plastic deformation is asymmetric with respect to direction of mechanical loading, as a result of specific relationships between the normal and resolved shear stress on active slip planes. This is attributed to the dependence of shear wave speed on the stress state acting on slip plane...

In this report, we present our twinning model intended for simulation of the dynamic deformation of metals with low values of the stacking fault energy, as well as the results of application of the model to numerical simulation of intensive loading of metals. Generation of a twin is described as an appearance of a stacking fault with size more than some critical value, while growth of a twin is...

We have investigated the propagation of {332}<113> twins in a multilayered Ti-10Mo-xFe (x = 1-3) alloy fabricated by multi-pass hot rolling. The material contains a macroscopic Fe-graded structure (about 130 μm width) between 1 and 3 wt% Fe in the direction perpendicular to rolling. We observe strong influence of the Fe-graded structure in the twin propagation behavior. The propagation of {332}...

Two different types of shear bands generate in ultrafine-grained (UFG) CoCrFeMnNi high-entropy alloys deformed at 77 K, i.e. commonly-observed low angle grain boundary (LAGB) type and unusual twin-coupled type. Twin-coupled exhibit a misorientation 56–67° with the matrix, contrast to LAGB band 6–12°. Both annealing twins deformation can act as precursor for bands, where dislocation accumulation...

Deformation twinning is an important mechanism occurring in certain types of diffusionless shear phase transformations for which the shear processes involve a non-lattice vector. In these cases, the deformation occurs through the nucleation and motion of partial dislocations or the glide of already present partial dislocations, which induce a structural change in the material. The generation an...

In this chapter, we highlighted the in situ transmission electron microscope (TEM) observation of the interactions of dislocations with three types of interfaces: (i) twin boundaries in Cu; (ii) metallic interphase boundaries; and (iii) metal/ceramic interfaces. Interface structures, interface properties, and dislocation-interface interactions are characterized in a high-resolution TEM. These k...

A multiscale model and numerical method for computing microstructures with large and inhomogeneous deformation is established, in which the microscopic and macroscopic information is recovered by coupling the finite order rank-one convex envelope and the finite element method. The method is capable of computing microstructures which are locally finite order laminates. Numerical experiments on a...