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In the presented model the microstructure of a functionally graded material (FGM) is accounted in two ways: via FGM properties and by distributed small cracks which could be on grain boundaries of the material. The contribution to the solution of material gradation of FGM and of material structure reflected via geometry of distributed cracks is investigated. Besides, some additional effects arising due to possible crack closure and contact of crack surfaces are taken into account in the model and its contribution is also assessed. The goal of this investigation is to show these affects and to estimate the contribution on the SIFs of each of these, if they are strong or can be neglected. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations of edge dislocation interactions with coherent and incoherent silver precipitates in the copper matrix are applied to investigate precipitation strengthening. Simulated shear tests with spherical and octahedral precipitates revealed that dislocations can cut a precipitate or circumvent it by the Orowan mechanism. Precipitates with radii below [ABSTRACT FROM AUTHOR]

Abstract: Our work is aimed to investigate the deformation behavior of Ag‐17vol.%SnO2 metal matrix composites under a hot extrusion process which causes extraordinarily large plastic deformations and recrystallization. The micro‐macro integrated axisymmetric finite element simulation is preferred for the first study, since it costs less calculation effort compared to 3D calculations, presents the mechanical variables in all 3D dimensions and the measured microstructure can be directly applied as the cross section. Due to that the volume (area) fraction of the particle phase in the selected 2D real microstructures often deviate from the real one, we show a numerical method to modify the EBSD‐images in order to match the 3D composition. This modification should be useful for FE simulations with a geometry based on a real microstructure. Considering that the tomograms are actually 2D images with a given distance in the 3rd dimension, such a modification with a further extension in the algorithm can also be applied for 3D microstructures based on tomograms to match the real composition. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Precipitation is one of the most important strengthening mechanisms in alloys. To investigate its effect on dislocation motion in copper‐silver alloys, molecular dynamics simulations of the interaction between an edge dislocation and silver precipitates within the copper matrix have been employed by Hocker et al. (article no. 1600479). The influence of size, shape and coherency of a precipitate on this quantity is especially of interest. It is revealed that the circumvention mechanism of the passing dislocation at the precipitate/matrix interface is a result of specific reactions with misfit dislocations, often leading to sessile segments. In the cover's top row a characteristic case of cutting is shown: The trailing partial and two Shockley partials (green) of the interface react to alternating Lomer‐Cottrell and Hirth locks (grey and yellow), dissolving only after the leading partial has passed the precipitate. The presence of full dislocations (blue) at the interface facilitates Orowan circumvention (middle row). The trailing partial reacts with a full dislocation to a Frank partial (cyan) which cannot dissolve. Orowan circumvention is often accompanied by cross‐slip. Recombination of crossslipped segments can occur on a plane differing from the initial glide plane, leading to the formation of a double jog (bottom row). [ABSTRACT FROM AUTHOR]

A kinetic Monte Carlo approach is used to study the influence of Cr, Fe, Al, or Mg addition on the precipitation in a Cu-Ni-Si alloy. The simulation method is based on a vacancy diffusion model. The crucial parameters of this method are the pairwise mixing energies of all contained elements which are determined by ab initio calculations. The number of dissolved atoms in equilibrium state is used to estimate the influence of Cr, Fe, Al, or Mg on the electrical conductivity. In order to estimate the influence of the alloying elements on strength ab initio calculations of misfit strain at the [ABSTRACT FROM AUTHOR]