Whole powder pattern modelling

Scardi, Paolo; Leoni, Matteo

doi:10.1107/s0108767301021298

Cited by 524 publications

(437 citation statements)

References 41 publications

Supporting

Mentioning

425

Contrasting

Unclassified

Order By: Relevance

“…Other factors such as dislocation density, slip activity [32], and the presence of stacking faults can also affect the shape and/or position of diffraction peaks [27]. Warren [39], Randle and Engler [40] developed the XRDLPA approach for the analysis of the microstructure, which was later followed by others [28,[41][42][43][44][45] with some modifications making it possible to determine the crystallite size and microstrain in materials reliably. Similarly to [16,23], the modified Rietveld [46] method has been used in order to characterise microstructures in this investigation.…”

Section: Methods Of X-ray Diffraction Line Profile Analysismentioning

confidence: 99%

The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti–Al–Mo–V–Cr–Fe alloys

Ahmed

Savvakin

Ивасишин

et al. 2013

Materials Science and Engineering: A

View full text Add to dashboard Cite

The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti-Al-Mo-V-Cr-Fe alloys AbstractTwo near-β titanium alloys, Ti-5Al-5Mo-5V-1Cr-1Fe and a modified one containing 2 wt% Cr (Ti-5Al-5Mo-5V-2Cr-1Fe) were produced from Ti hydride precursor powders via the cost-effective blended elemental powder metallurgy technique. The effects of two cooling rates (10 K s−1 and 1 K s−1) during thermo-mechanical processing on the microstructure and mechanical properties were investigated using X-ray diffraction and scanning electron microscopy. X-ray line profile analysis revealed that dislocation densities and microstrain in β-Ti phase are higher than in α-Ti phase for all cases. In both alloys, slower cooling results in an increase in α volume fraction and promotes morphology of continuous grain boundary α phase. A lower total elongation is obtained in both alloys under slower cooling which could be accounted for by the continuous morphology of α phase. Overall, Ti-5Al-5Mo-5V-1Cr-1Fe displays higher ultimate tensile strength and total elongation compared to Ti-5Al-5Mo-5V-2Cr-1Fe, regardless of the cooling rate. Two near-β titanium alloys, Ti-5Al-5Mo-5V-1Cr-1Fe and a modified one containing 2 wt. % Cr (Ti-5Al-5Mo-5V-2Cr-1Fe) were produced from Ti hydride precursor powders via the cost-effective blended elemental powder metallurgy technique. The effects of two cooling rates (10 Ks -1 and 1 Ks -1 ) during thermo-mechanical processing on the microstructure and mechanical properties were investigated using X-ray diffraction and scanning electron microscopy. X-ray line profile analysis revealed that dislocation densities and microstrain in β-Ti phase are higher than in α-Ti phase for all cases. In both alloys, slower cooling results in an increase in α volume fraction and promotes morphology of continuous grain boundary α phase. A lower total elongation is obtained in both alloys under slower cooling which could be accounted for by the continuous morphology of α phase. Overall, Ti-5Al-5Mo-5V-1Cr-1Fe displays higher ultimate tensile strength and total elongation compared to Ti-5Al-5Mo-5V-2Cr-1Fe, regardless of the cooling rate.

show abstract

Section: Methods Of X-ray Diffraction Line Profile Analysismentioning

confidence: 99%

The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti–Al–Mo–V–Cr–Fe alloys

Ahmed

Savvakin

Ивасишин

et al. 2013

Materials Science and Engineering: A

View full text Add to dashboard Cite

show abstract

“…Data were analysed using the Whole Powder Pattern Modelling (WPPM) method [44] implemented in the PM2K software [45]. The instrumental resolution function was characterised with the NIST SRM 660a (LaB6) standard [46,45]: all peak profiles of the LaB6 phase were simultaneously fitted with symmetrical pseudo-Voigt functions whose width and shape were constrained according to the Caglioti et al formulae [47].…”

Section: Characterisation Techniquesmentioning

confidence: 99%

Microemulsion Synthesis of Copper Oxide Nanorod-Like Structures

Dodoo‐Arhin

Leoni

Scardi

2012

Molecular Crystals and Liquid Crystals

Self Cite

View full text Add to dashboard Cite

Copper oxide (CuO) nanorod-like structures made of spherical nanocrystals were synthesized at moderate temperature (80°C) starting from CuCl 2 •2H 2 O crystals in a water/n-heptane microemulsion stabilised by the nonionic Brij-30 surfactant. Whole Powder Pattern Modelling of the X-ray diffraction pattern shows absence of linear and planar defects with crystalline domains in the range of 4 -8 nm. A linear correlation between the average size of the particles and the quantity of water in the system was observed: all synthesised specimens show a large blue shift of the energy bandgap (up to 2.7 eV versus 1.2 eV of bulk CuO) resulting from quantum confinement effects. The mechanism of growth of the spherical nanoparticles into nanorod-like structures has been elucidated.

show abstract

“…This is, in turn, convoluted with the specimen broadening function to yield the observation. With whole powder pattern modeling (WPPM) (Scardi & Leoni, 2002), the character of the specimen broadening function is analyzed using functions that explicitly correlate the observation to the microstructural character of the specimen: the result is the set of parameters for the chosen models that are able to best interpret the observation. The term "microstructure" is here employed in a broad sense and includes all specimen-related features that interrupt the regular periodicity of the lattice.…”

Section: Introductionmentioning

confidence: 99%

Crystalline domain size and faulting in the new NIST SRM 1979 zinc oxide

et al. 2013

Self Cite

View full text Add to dashboard Cite

A NIST SRM certified to address the issue of crystallite size measurement through a line profile analysis has been under development for several years. In order to prepare the feedstock for the SRM, nano-crystalline zinc oxide was produced from thermal decomposition of zinc oxalate.The thermal processing parameters were chosen to yield particles in two size ranges, one with a distribution centered at approximately 15 nm and another centered at 60 nm. Certification data were collected on a NIST-built diffractometer equipped with a Johansson incident beam monochromator and scintillation detector. Data were analyzed using whole powder pattern modeling to determine microstructural data. The analysis shows domains to be in the form of discs of a fairly small aspect ratio. While both materials exhibit the effects of stacking faults through broadening of specific hkl reflections, their presence in the 60 nm is more difficult to discern. Images of the crystallites obtained with transmission electron microscopy are consistent with the results from the X-ray diffraction analyses.

show abstract

Whole powder pattern modelling

Cited by 524 publications

References 41 publications

The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti–Al–Mo–V–Cr–Fe alloys

The effect of cooling rates on the microstructure and mechanical properties of thermo-mechanically processed Ti–Al–Mo–V–Cr–Fe alloys

Microemulsion Synthesis of Copper Oxide Nanorod-Like Structures

Crystalline domain size and faulting in the new NIST SRM 1979 zinc oxide

Contact Info

Product

Resources

About