Micro-strains in cold rolled Cu–Nb nanolayered composites determined by X-ray line profile analysis

Strain rate sensitivity of nanolayered Cu/X (X=Cr, Zr) micropillars: Effects of heterophase interface/twin boundary

“…As for the softening behavior, there are several mechanisms that are closely linked to the deformation morphologies of the samples. The possible underlying mechanisms for the softening at relatively greater plastic strains ( 45%) are as follows: (i) for the nanolayered pillars with h450 nm, the dislocations annihilation within the layers can lead to the softening behavior at great strains [82,83], and only the uniform thinning of layers (extrusion of Cu) is observed (Figs. 9a and 10a); (ii) for the nanolayered pillars with 50 ZhZ25 nm at great strains, the external stress overwhelms the interfacial barrier and/or a geometrical stress concentration such as a pillar corner imposes a nonuniaxial stress state, unbalanced slip on intralayer slip switches on and causes rotation of the interface plane i.e., geometrical softening [57,74] (see Figs.…”

Size effect on mechanical behavior of Al/Si3N4 multilayers by nanoindentation

“…However, when the layer thickness is further decreased to the range of 10-50 nm, there is not enough space to accommodate dislocation pileup in the individual layers, and Orowan-type bowing of individual dislocations becomes dominated and the increase of strength follows with t b t ln / / flow σ ∝ ( ) [8]. The statistically-stored dislocations and geometrically-necessary dislocations were studied with the metallic multilayers (Cu/Nb) and nanostructures (Sn nanopillars) composites the synchrotron X-ray microdiffraction technique [45][46][47][48][49].…”

Plasticity in the nanoscale Cu/Nb single-crystal multilayers as revealed by synchrotron Laue x-ray microdiffraction

“…However, previous studies 6,7 on deformation of metallic multilayered composite materials have been largely done ex situ and using a conventional laboratory x-ray diffraction (XRD) technique that sampled a rather large area of the material (;hundreds of microns). Lacking the sensitivities needed in the deformation of such small length scale materials, these studies did not reveal much contrast in terms of dislocation density and cell structure formation within layers between before and after the deformation.…”

“…Lacking the sensitivities needed in the deformation of such small length scale materials, these studies did not reveal much contrast in terms of dislocation density and cell structure formation within layers between before and after the deformation. 6,7 In situ study of metallic multilayered thin films utilizing a high brilliance synchrotron source and mesoscale (tens to hundreds of microns) x-ray beams a) was conducted by Aydiner et al, 8,9 resulting in the measurements of residual stress prior to deformation and elastic-plastic transition during tensile straining. However, as inherent in the tensile deformation mode of materials, samples would be more prone to fracture (as opposed to in compression deformation) before much plasticity could be studied.…”