A5020605355- Microstructure and mechanical properties
- Metal and Thin Film Mechanics
- High-Velocity Impact and Material Behavior
- Boron and Carbon Nanomaterials Research
- Microstructure and Mechanical Properties of Steels
- Intermetallics and Advanced Alloy Properties
- High-pressure geophysics and materials
- Shape Memory Alloy Transformations
- High Temperature Alloys and Creep
- Metallurgical and Alloy Processes
- Advanced materials and composites
- Material Properties and Failure Mechanisms
- Education, Psychology, and Social Research
- Fatigue and fracture mechanics
- Hydrogen embrittlement and corrosion behaviors in metals
- Electromagnetic Effects on Materials
- Mechanical Behavior of Composites
- Magnetic Properties of Alloys
- Advanced ceramic materials synthesis
- Magnetic properties of thin films
- Historical Legal Studies and Society
- Semiconductor materials and interfaces
- Advanced Materials Characterization Techniques
- GaN-based semiconductor devices and materials
- Mechanical and Thermal Properties Analysis
Brno University of Technology
2015-2024
Central European Institute of Technology
2015-2024
University of Ostrava
2022
Czech Technical University in Prague
2015-2020
Czech Academy of Sciences, Institute of Physics of Materials
2013-2020
Medizinisches Versorgungszentrum Prof. Mathey, Prof. Schofer
2018
Ab initio electronic structure calculations of the ideal strength Fe, Co, Ni, and Cr under isotropic tension were performed using linear muffin-tin orbital method in atomic sphere approximation. Magnetic ordering was taken into account by means a spin-polarized calculation. Two approximations for exchange-correlation term employed: namely, local (spin) density approximation generalized gradient Computed values equilibrium lattice parameters, bulk moduli, magnetic moments compared with...
Elastic response and strength of perfect crystals is calculated for triaxial loading conditions from first principles. The stress state constituted by uniaxial tensile superimposed transverse biaxial stresses. maximum evaluated as a function the Results eight cubic metals two orientations ($⟨110⟩$ $⟨111⟩$) primary axis are presented compared with data $⟨100⟩$ direction loading. Obtained results show that, within studied range stresses, monotonically increases increasing most metals. Within...
A simulation of a tensile test copper crystal along the [001] direction is performed using Vienna ab initio package (VASP). Stability conditions for uniaxially loaded system are presented and analysed ideal (theoretical) strength loading determined to be 9.4 GPa in tension 3.5 compression. comparison with experimental values performed.
Critical shear stress under the superimposed hydrostatic and uniaxial normal conditions of C, Si, Ge, SiC is evaluated by ab initio density functional theory calculations to investigate response ideal strength (ISS) stresses in covalent crystals. We find a substantial difference responses ISS among crystals examined; e.g., compression increases C but decreases that SiC. The mostly highly nonlinear anisotropic function stress. results thus indicate can significantly affect critical stress,...
Despite the absence of band gap calculated for MAX phases, experimental analysis showed crucial role that impurities play in photoelectrochemical hydrogen generation, leading to better performances thanks their intrinsic photoactivity.
Influence of biaxial stresses applied perpendicularly to the [100] loading axis on theoretical tensile strength is studied from first principles. Ten crystals cubic metals and three diamond ceramics were selected as particular case studies. Obtained results show that, within a limited range stresses, monotonously increases with increasing stress for most metals. Within range, dependence can be approximated by linear function. Beyond shows maximum that usually appears in stresses. On other...
Four different models (corresponding to loading conditions) of first principles tensile tests are employed determine cohesion and strength several interfaces, namely coherent interfaces two fcc metals (Ni/Ag Ni/Cu) symmetrical tilted Σ5(210) grain boundary in nickel (clean as well sulfur-decorated). The purpose this study is compare the selected critically discuss their advantages limitations. Particular attention paid differences predictions, ability identify weakest link studied system...
This work presents a simple way of estimating uniaxial tensile strength on the basis theoretical shear calculations, taking into account its dependence superimposed normal stress. The presented procedure enables us to avoid complicated and time-consuming analyses elastic stability crystals under loading. atomistic simulations coupled deformations in cubic are performed using first principles computational code based pseudo-potentials plane wave set. Six fcc subjected convenient slip systems...
The response of three covalent crystals with a diamond lattice (C, Si and Ge) to uniaxial special triaxial (generally nonhydrostatic) loading is calculated from first principles. deformations are described in terms variations bond lengths angles. stress state simulated as superposition axial tension or compression transverse (both tensile compressive) biaxial stresses. stresses considered be adjustable parameters the theoretical strengths along 〈100〉, 〈110〉, 〈111〉 crystallographic directions...
This work demonstrates a simple but efficient way as to how determine the existence of shear instabilities in ideal bcc crystals under uniaxial loading. The theoretical tensile strengths are derived from calculated values strength and their dependence on superimposed normal stress. presented procedure enables us avoid complicated time-consuming analyses elastic stability crystals. Results first-principles simulations coupled deformations for two most frequent slip systems...
Two fcc crystals, Ni and Ir, are subjected to simulated isotropic uniaxial tension along the direction. Their structural stability is assessed by analyzing phonon spectra that calculated from first principles for different values of strain. A relevant analysis elastic conditions also performed. Predicted instabilities correspond well those associated with soft phonons vanishing wavevectors. Although most previous studies predicted in crystals macroscopic (elastic) instabilities, we found...
Lattice dynamics and stability of four fcc crystals (Al, Ir, Pt Au) under isotropic (hydrostatic) tensile loading are studied from first principles using the linear response method harmonic approximation. The results reveal that, contrary to former expectations, strengths all limited by instabilities related soft phonons with finite or vanishing wavevectors. critical strains associated such remarkably lower than those volumetric instability. On other hand, corresponding reduction strength is...
Abstract Principles and advantages of a new concept based on the ab initio aided strain gradient elasticity theory are shown in comparison with classical Barenblatt cohesive model. The method is applied to theoretical prediction critical energy release rate crack tip opening displacement at instability nanopanels made germanium molybdenum crystals. necessary length scale parameter l 1 determined for by best fits computed screw dislocation displacements phonon dispersions. Values rates...