We investigate the deformation behavior of bimetallic and trimetallic nanoscale multilayer metallic composites under biaxial loading using molecular dynamics. Three types structures were studied: (a) Cu–Ni fcc/fcc bilayer, (b) Cu–Nb fcc/bcc (c) Ni–Cu–Nb fcc/fcc/bcc trilayer. A configuration with a dislocation structure inside is generated by initially perfect to high strain nucleate dislocations, then completely unloading it again. The comparison between bilayer trilayer revealed that more...

The strain hardening and the related surface pile-up phenomena in CuNi, CuNb CuNiNb nanoscale multilayered metallic (NMM) composites are investigated using atomistic simulations of nanoindentation on such multilayers with varying individual layer thickness. Using empirical load-stress displacement-strain relations, obtained load-depth curves were converted to hardness-strain which was then fitted power law. It is found that extent inversely exponent NMMs. Two deformations mechanisms control...

The deformation mechanisms in Cu-Ni-Cu composite nanowires subjected to uniaxial tensile loading are investigated using molecular-dynamics simulations. We particularly explore the coupled effects of geometry and coherent interface on tendency deform via twins show pseudoelastic behavior. It is found that critical size exhibit pseudoelasticity $5.6\ifmmode\times\else\texttimes\fi{}5.6\text{ }{\text{nm}}^{2}$, which 6.5 times greater than single-crystalline Cu nanowires. Our results also offer...

In latent interactions of dislocations, junction formation is one the most important phenomena that contribute to evolution strength. this work, hardening coefficients for pure aluminum are estimated using 3D multiscale dislocation dynamics program (MDDP). Three well-known configurations, namely, Hirth lock, glissile junction, and Lomer studied discrete simulations. The strength discussed as a function resolved shear stress (RSS) number junctions three investigated. lock found be weakest...

Abstract Mapping of residual stresses at the mesoscale is increasingly practical thanks to technological developments in electron backscatter diffraction (EBSD) and X-ray microdiffraction using high brilliance synchrotron sources. An analysis presented a Cu single crystal deformed compression about 10% macroscopic strain. Local orientation measurements were made on sectioned polished specimens EBSD microdiffraction. In broad strokes, results are similar each other with orientations being...

To study the strain hardening in nanoscale multilayer metallic (NMM) composites, atomistic simulations of nanoindentation are performed on CuNi, CuNb, and CuNiNb multilayers. The load-depth data were converted to hardness-strain that then modeled using power law. plastic deformation multilayers is closely examined. It found incoherent CuNb NiNb interfaces stronger than coherent CuNi interface. parameters discovered be related density dislocations interfaces, which turn have law dependence...

Nanostructured metallic material (NMM) composites are a new class of materials that exhibit high structural stability, mechanical strength, ductility, toughness and resistance to fracture fatigue; these properties suggest can play leading role in the future micromechanical devices. However, before those put into service any significant applications, many important fundamental issues remain be understood. Among them, is question strengthening NMM using second phase particles if addition...

We investigate the pseudoelastic behavior at room temperature of composite nanowires using molecular dynamics simulations. The are composed a nickel core surrounded by copper shell, leading to high coherency stresses. and surface stresses cause undergo lattice reorientation, twinning, from ⟨001⟩ ⟨110⟩ during relaxation. Nanowires different cross-sectional areas (varying 2.17×2.17 up 2.9×2.9 nm2) were studied. In all cases, under tensile loading, reorient then unloading back ⟨110⟩, thus...

We investigated numerically the number of sites visited ${\mathit{S}}_{\mathit{N}}$ by random walks on backbone structure percolation cluster at critical threshold. This quantity can be predicted scaling conjecture in terms fractal and random-walk dimensions (${\mathit{d}}_{\mathit{f}}$ ${\mathit{d}}_{\mathit{w}}$). Our results confirm this with time, similarly to cluster. The exponent (spectral dimension) is calculated, it found ${\mathit{d}}_{\mathit{s}}^{\mathrm{BB}}$=1.23, while predicts...

Amongst the many adaptive features of a bivalve shell, valve shape has been hypothesised to increase structural stability and aid in withstanding crushing predation. Using Finite Element Analysis we modelled attack crab on hard clam, soft blue mussel, assessing effect shell shape, size thickness their performance. Nanoindentation tests provide data material properties. The clam is best suited distribute applied loads evenly over thick shell. Blue mussel shells work well when they are thin,...