Quantitative Characterization of Precipitate Microstructures in Metallic Alloys Using Small-Angle Scattering

Deschamps, A.; Geuser, F. de

doi:10.1007/s11661-012-1435-7

Cited by 58 publications

(34 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition, it has to be mentioned that the relative uncertainties of the volume fraction calculations cannot be expected to be better than ±10%. This is due to the uncertainties related to the absolute intensity calibration, the extrapolations of the data to 0 and infinity, and the assumptions of the chemical composition of the precipitates [26].…”

Section: Small-angle Scatteringmentioning

confidence: 99%

Modeling of GP(I) zone formation during quench in an industrial AA7449 75 mm thick plate

et al. 2016

View full text Add to dashboard Cite

The GP(I) zone formation during quench is simulated in an industrial Aluminum alloy AA7449 75 mm thick plate by using a multi-class precipitation model. For this purpose, results of in situ SAXS experiments are reported. A methodology is presented that takes advantage of the collected data to derive i -a thermodynamic description for GP(I) zones from reversion heat treatments by using a solubility product and ii -the influence of excess vacancies on diffusion coefficients. This approach allows reproducing reasonably well the GP(I) zone formation measured during rapid cooling. Further, the simulated as-quenched surface yield strength compares well with experimental results reported in the literature.

show abstract

Section: Small-angle Scatteringmentioning

confidence: 99%

Modeling of GP(I) zone formation during quench in an industrial AA7449 75 mm thick plate

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Determination of Q necessitates integration between q=0 and q=∞ which is an extremely difficult procedure as described in detail in reference [34]. In the present study, the approach used was to fit the Iq 2 vs q data with a lognormal distribution and extrapolate the fit to 0 and ∞.…”

Section: Quantification Of Precipitate Developmentmentioning

confidence: 99%

Characterising precipitate evolution in multi-component cast aluminium alloys using small-angle X-ray scattering

Wang

McCartney

et al. 2017

Journal of Alloys and Compounds

View full text Add to dashboard Cite

The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. AbstractAluminium alloys can be strengthened significantly by nano-scale precipitates that restrict dislocation movement. In this study, the evolution of inhomogenously distributed trialuminide precipitates in two multi-component alloys was characterised by synchrotron small-angle Xray scattering (SAXS). The appropriate selection of reference sample and data treatment required to successfully characterise a low volume fraction of precipitates in multi-component alloys via SAXS was investigated. The resulting SAXS study allowed the analysis of statistically significant numbers of precipitates (billions) as compared to electron microscopy (hundreds). Two cast aluminium alloys with different volume fractions of Al3ZrxV1-x precipitates were studied. Data analysis was conducted using direct evaluation methods on SAXS spectra and the results compared with those from transmission electron microscopy (TEM). Precipitates were found to attain a spherical structure with homogeneous chemical composition. Precipitate evolution was quantified, including size, size distribution, volume fraction and number density. The results provide evidence that these multi-component alloys have a short nucleation stage, with coarsening dominating precipitate size. The coarsening rate constant was calculated and compared to similar precipitate behaviour.2

show abstract

“…15 Structural information, such as Guinier radius (R g ) and scattering invariant (Q), were extracted from the scattering data by using a modelindependent analysis as performed by Deschamps and de Geuser. 16,17 The average particle size was estimated using a self-consistent Guinier approximation. 16 The uncertainty of the Guinier radius was calculated from the error associated with the slope of the linear Guinier fit.…”

mentioning

confidence: 99%

“…The volume fractions of the two phases were obtained from the scattering invariant, which corresponds to the integral of the Kratky plot from 0 to infinity. 17 The minimum between the two scattering contributions in the Kratky plot (Figure 1) was used to separate the invariants of both phases. The contribution at high q-values was extrapolated from a q-value of 0.07 Å À1 to 0, instead of 0.007 Å À1 for the whole scattering spectra.…”

mentioning

confidence: 99%

“…20 The accuracy of the volume fraction estimation cannot be expected to be better than 610% due to the uncertainties related to the absolute intensity calibration, the extrapolations of the data in low-q and high-q regions, and assumptions of the chemical composition. 17 The number density of the precipitates was calculated by N ¼ f v =ð4=3pR 3 g Þ. It has to be noted that, due to the measurable momentum transfer having been limited to q !…”

mentioning

confidence: 99%

See 1 more Smart Citation

Early precipitation during cooling of an Al-Zn-Mg-Cu alloy revealed by in situ small angle X-ray scattering

Schloth

Wagner

Fife

et al. 2014

Applied Physics Letters

View full text Add to dashboard Cite

Early subnanometre cluster formation during quenching of a high-strength AA7449 aluminium alloy was investigated using in situ small angle X-ray scattering. Fast quench cooling was obtained by using a laser-based heating system. The size and number density of homogeneous nucleated clusters were found to be strongly dependent on the cooling rate, while the volume fraction of cluster formation is independent of the cooling rate. Heterogeneous larger precipitation starts at higher temperatures in volume fractions that depend on the cooling rate. V C 2014 AIP Publishing LLC. The fabrication of aluminium alloys involves a number of thermomechanical steps such as solute-heat treatment followed by fast cooling, i.e., quenching. It is well known that the cooling rate influences the homogeneous and heterogeneous formation of precipitates and that the effect of these differences on the mechanical properties cannot be removed by additional aging. The typical precipitation sequence of the equilibrium g phase (Mg(Zn,Cu,Al) 2 ) in the Al-Zn-Mg(-Cu) system is: GPZ ! g 0 ! g. 1 Early studies by Lendvai and L€ offler on Al-Zn-Mg alloys report that vacancy-rich clusters (VRC), acting as nucleation sites for Guinier Preston zones (GPZ), can form during the cooling from the solutionizing temperature. 2,3 The number of VRCs strongly depends on the quench parameters influencing the excess vacancies in the structure. Clusters formed by only a few atoms 4 have been identified using 3D atom probe. Despite their small size, the clusters are effective in increasing the yield strength of the material. 5 In addition to the VRCs, heterogeneous precipitation of the equilibrium g phase occurs at higher temperatures. 1 It is therefore not surprising that when producing thick Al alloy plates, the resultant precipitation size, density, and volume fraction are expected to differ across the plate because of the difference in cooling rates. The latter creates residual stresses at as quenched temper that are reduced by stress relief. The remaining residual stresses at final temper may lead to machining distortions. To investigate the influence of precipitation on residual stresses, thermomechanical models linking solid-state transformations to the final stress distribution have to be developed. Such simulation schemes need input on size, density, and volume fraction of precipitation as function of cooling rates that can only be provided by experimentation.Small angle X-ray scattering (SAXS) has proven to be a useful tool for the investigation of precipitation phenomena. 6 SAXS is a well established technique for investigating clusters with high contrast in atomic number with respect to the matrix. SAXS has been used extensively to study precipitation phenomena in Al alloys ex situ and also in situ during aging. [6][7][8] Providing information on the size and volume fraction of the precipitates, SAXS validated thermodynamic-based precipitation model predictions 7,9 of the effect of aging on precipitation. There is however no information to be gathered...

show abstract

Quantitative Characterization of Precipitate Microstructures in Metallic Alloys Using Small-Angle Scattering

Cited by 58 publications

References 52 publications

Modeling of GP(I) zone formation during quench in an industrial AA7449 75 mm thick plate

Modeling of GP(I) zone formation during quench in an industrial AA7449 75 mm thick plate

Characterising precipitate evolution in multi-component cast aluminium alloys using small-angle X-ray scattering

Early precipitation during cooling of an Al-Zn-Mg-Cu alloy revealed by in situ small angle X-ray scattering

Contact Info

Product

Resources

About