A5010996601- Microstructure and mechanical properties
- Microstructure and Mechanical Properties of Steels
- X-ray Diffraction in Crystallography
- Aluminum Alloy Microstructure Properties
- Aluminum Alloys Composites Properties
- Metal and Thin Film Mechanics
- Fusion materials and technologies
- Nuclear Materials and Properties
- Advanced ceramic materials synthesis
- Advanced materials and composites
- High Temperature Alloys and Creep
- High-pressure geophysics and materials
- Metallurgy and Material Forming
- Magnesium Alloys: Properties and Applications
- Powder Metallurgy Techniques and Materials
- Ion-surface interactions and analysis
- High-Temperature Coating Behaviors
- Diamond and Carbon-based Materials Research
- Hydrogen embrittlement and corrosion behaviors in metals
- Metal Forming Simulation Techniques
- High Entropy Alloys Studies
- Boron and Carbon Nanomaterials Research
- Advanced Materials Characterization Techniques
- Fatigue and fracture mechanics
- Additive Manufacturing Materials and Processes
University of Manchester
2016-2024
Eötvös Loránd University
2015-2024
Virginia Tech
2019
Hospital Damas
2016
Université de Lorraine
2016
City University of Hong Kong
2013-2015
Institute of Materials and Environmental Chemistry
2008
Institut Laue-Langevin
2005
Austrian Academy of Sciences
2004
Siemens (Germany)
2000
The x-ray line profiles of an ultrafine grained copper crystal, produced by equal-channel angular pressing, were measured a special high resolution diffractometer with negligible instrumental broadening. analysis the breadths and Fourier coefficients have shown that taking into account contrast caused dislocations on gives new scaling factors in Williamson–Hall plot Warren–Averbach analysis, respectively. When strain is procedure proposed here enables straightforward determination particle...
It has been shown recently that in many cases strain anisotropy powder diffraction can be well accounted for by the dislocation model of mean square strain. The practical application assumes knowledge individual contrast factors C dislocations related to particular Burgers, line and vectors or average C¯ . A simple procedure experimental determination worked out, enabling character terms a parameter q values were determined numerically wide range elastic constants cubic crystals. parameters...
Two different methods of diffraction profile analysis are presented. In the first, breadths and first few Fourier coefficients profiles analysed by modified Williamson–Hall Warren–Averbach procedures. A simple pragmatic method is suggested to determine crystallite size distribution in presence strain. second, measured physical fitted well established ab initio functions strain profiles. both procedures, anisotropy rationalized dislocation model mean square The procedures applied tested on a...
A computer program has been developed for the determination of microstructural parameters from diffraction profiles materials with cubic or hexagonal crystal lattices. The measured their Fourier transforms are fitted by ab initio theoretical functions size and strain broadening. In calculation functions, it is assumed that crystallites have log-normal distribution caused dislocations. Strain anisotropy taken into account dislocation contrast factors ellipticity crystallites. fitting...
Anisotropic strain broadening in X-ray line profile analysis means that the width of diffraction profiles Bragg reflections is not a monotonous function angle. The lack physically sound model makes interpretation and structure refinement procedure Rietveld often difficult or even impossible. A simple straightforward presented for rationalisation anisotropic terms contrast effect dislocations dislocation-like lattice defects. evaluation particle size coherent domain size, density arrangement...
Abstract Catastrophic accidents caused by fatigue failures often occur in engineering structures. Thus, a fundamental understanding of cyclic-deformation and fatigue-failure mechanisms is critical for the development fatigue-resistant structural materials. Here we report high-entropy alloy with enhanced life ductile-transformable multicomponent B2 precipitates. Its are revealed real-time in-situ neutron diffraction, transmission-electron microscopy, crystal-plasticity modeling, Monte-Carlo...
Abstract Energy efficiency is motivating the search for new high-temperature (high-T) metals. Some body-centered-cubic (BCC) random multicomponent “high-entropy alloys (HEAs)” based on refractory elements (Cr-Mo-Nb-Ta-V-W-Hf-Ti-Zr) possess exceptional strengths at high temperatures but physical origins of this outstanding behavior are not known. Here we show, using integrated in-situ neutron-diffraction (ND), high-resolution transmission electron microscopy (HRTEM), and recent theory, that...
Abstract Copper single crystals oriented for multiple slip with [001] axes have been deformed in tension and investigated by X-ray line-broadening measurements using {002} Bragg reflections. The intensity distributions of the broadened line profiles exhibit an asymmetry whose 'sign' depends on particular reflection used. It is shown that asymmetric are due to superposition two mutually displaced symmetrically profiles. These sub-profiles can be ascribed material located cell walls interiors...
A systematic procedure is developed to evaluate the density of planar defects together with dislocations and crystallite or subgrain size by x-ray line profile analysis in fcc crystals. Powder diffraction patterns are numerically calculated using DIFFAX software for intrinsic extrinsic stacking faults, twin boundaries first 15 Bragg reflections up 20% fault density. It found that consist five subreflection types categorized specific selection rules hkl indices accordance theory Warren [Prog....
The computer program ANIZC has been developed using the Pascal programming language for calculation of diffraction contrast factors dislocations in elastically anisotropic cubic, hexagonal and trigonal crystals. factor is obtained numerically by integrating angular part distortion tensor slip plane. calculated solving sextic equation provided mechanical equilibrium a single dislocation an infinite medium. can be used interpretation strain anisotropy as from peak profile measurements made on...
Crystallite size determined by X-ray line profile analysis is often smaller than the grain or subgrain obtained transmission electron microscopy, especially when material has been produced plastic deformation. It shown that besides differences in orientation between grains subgrains, dipolar dislocation walls without also break down coherency of X-rays scattering. This means coherently scattering domain provided provides cell bounded boundaries walls.
Strain anisotropy can be well accounted for by the dislocation model of lattice distortion. In a texture-free powder or polycrystal, if all possible Burgers vectors are equally populated, contrast factors linear function fourth-order invariants hkl indices. Using this relation have been evaluated numerically and compiled number common hexagonal materials. A procedure is presented to match experimentally determined factor parameters with obtained parameter values. The used as tool extract...
X-ray diffraction line profiles of plastically deformed Cu single crystals orientated for ideal multiple slip were recently found to be markedly asymmetric. A theory is developed interpret this kind asymmetric broadening in terms the average dislocation density, dipole polarization structure and mean square fluctuation density.