Crystallite size and lattice strain in nanocrystalline Ni–Mo alloys studied by Rietveld refinement

Karolus, M.; Łągiewka, E.

doi:10.1016/j.jallcom.2003.08.044

Cited by 74 publications

(37 citation statements)

References 11 publications

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“…We roughly estimated the dislocation density through the Williamson-Hall method, a widely used first approximation to assess the effects of micro strain and crystallite size [33,34]. In this approach, the true XRD peak broadening b (the observed peak broadening deducting the instrument broadening) consists of two parts: the crystallite size broadening b G and the strain broadening b S [35,36], and based on the assumption of Cauchy-type function, they are:…”

Section: Dislocation Hardeningmentioning

confidence: 99%

A precipitation-hardened high-entropy alloy with outstanding tensile properties

et al. 2016

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a b s t r a c tRecent studies indicated that high-entropy alloys (HEAs) possess unusual structural and thermal features, which could greatly affect dislocation motion and contribute to the mechanical performance, however, a HEA matrix alone is insufficiently strong for engineering applications and other strengthening mechanisms are urgently needed to be incorporated. In this work, we demonstrate the possibility to precipitate nanosized coherent reinforcing phase, i.e., L1 2 -Ni 3 (Ti,Al), in a fcc-FeCoNiCr HEA matrix using minor additions of Ti and Al. Through thermomechanical processing and microstructure controlling, extraordinary balanced tensile properties at room temperature were achieved, which is due to a well combination of various hardening mechanisms, particularly precipitation hardening. The applicability and validity of the conventional strengthening theories are also discussed. The current work is a successful demonstration of using integrated strengthening approaches to manipulate the properties of fcc-HEA systems, and the resulting findings are important not only for understanding the strengthening mechanisms of metallic materials in general, but also for the future development of high-performance HEAs for industrial applications.

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Section: Dislocation Hardeningmentioning

confidence: 99%

A precipitation-hardened high-entropy alloy with outstanding tensile properties

et al. 2016

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“…It is also known that the broadening of the XRD peak is related to the refinement of crystallite size that typically occurs with an increasing Mo content [31]. According to the literature, the mean crystallite size of Ni-Mo coatings can decrease from 50 to 2 nm by increasing the Mo content from 1 to 38 at.%, respectively [35,37,54]. This corresponds to a crystallite size of the investigated Ni-Mo coatings as small as~2 nm.…”

Section: Design Of Mo-rich Alloys Coatingsmentioning

confidence: 72%

Design of Highly Active Electrodes for Hydrogen Evolution Reaction Based on Mo-Rich Alloys Electrodeposited from Ammonium Acetate Bath

et al. 2019

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The given research was driven by prospects to design Mo-rich coatings with iron group metals electrodeposited from a highly saturated ammonium acetate bath. The obtained coatings could be employed as prominent electrodes for the hydrogen evolution reaction (HER). It was found that the Mo content in Ni–Mo alloys can be tuned from 30 to 78 at.% by decreasing the molar ratio [Ni(II)]:[Mo(VI)] in the electrolyte from 1.0 to 0.25 and increasing the cathodic current density from 30 to 100 mA/cm2. However, dense cracks and pits are formed due to hydrogen evolution at high current densities and that diminishes the catalytic activity of the coating for HER. Accordingly, smoother and crack-free Ni–54 at.% Mo, Co–52 at.% Mo and Fe–54 at.% Mo alloys have been prepared at 30 mA/cm2. Their catalytic behavior for HER has been investigated in a 30 wt.% NaOH solution at temperatures ranging from 25 to 65 °C. A significant improvement of electrocatalytic activity with increasing bath temperature was noticed. The results showed that the sequence of electrocatalytic activity in alkaline media decreases in the following order: Co–52 at.% Mo > Ni–54 at.% Mo > Fe–54 at.% Mo. These peculiarities might be linked with different catalytic behavior of formed intermetallics (and active sites) in electrodeposited alloys. The designed electrodeposited Mo-rich alloys have a higher catalytic activity than Mo and Pt cast metals.

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“…7. The received values of R-factors are typical for other nanomaterials [14][15][16] and they are presented in Table 3. The values are in a range of: R p : 13-18%, R wp : 17-22%, R exp : 8-9% and S: 1.9-2.3%.…”

Section: Resultsmentioning

confidence: 99%

“…After the crystallisation process the crystallite size and the lattice strain were calculated basing on the Williamson-Hall method [13], which was successfully, applied to many others nanomaterials and semi-amorphous materials (∼10Å) [14][15][16]. The line breadth was defined by the full width at half maximum.…”

Section: Materials and Research Methodologymentioning

confidence: 99%