Temporal evolution of coherent precipitates in an aluminum alloy W319: A correlative anisotropic small angle X-ray scattering, transmission electron microscopy and atom-probe tomography study

Abstract

Small-angle X-ray scattering (SAXS), transmission electron-microscopy (TEM), and atom-probe tomography (APT) are utilized correlatively to study the evolution of nanometer length-scale coherent precipitates in a commercial age-hardenable aluminum alloy, W319. SAXS, with its high-field-of-view and resultant large statistics, perfectly complements TEM and APT at the nanometer length-scale. The combined results provide a comprehensive description of the evolution of the fine precipitates. W319 exhibits two types of fine coherent precipitates on aging namely, ′ and Q, whose temporal evolution has been studied using time-resolved in situ SAXS analyses at three different aging temperatures: 438, 463, and 533 K. Complementary information about the morphology, dimensions and number density of the precipitates were determined from ex situ APT and TEM analyses. Coherent precipitates from a single grain of the -Al-matrix of W319 give rise to an anisotropic SAXS signal, which is subsequently simulated, taking into account the relative orientation of the sample and the crystallographic orientation relationships of the different precipitates. The simulated anisotropic SAXS intensity, based on the results from APT and TEM, is validated utilizing the experimentally obtained 2D SAXS patterns. This permits us to determine the dimensions and number densities of the precipitates from anisotropic SAXS signals, and a complete quantitative analysis of the in situ temporal evolution of the coherent precipitates is performed. Additionally, the present study demonstrates an alternative technique for extracting structural parameters from anisotropic SAXS analyses. The methodology presented herein will be useful for age-hardening analyses of commercial agehardenable Al-based alloys and Ni-based super alloys.

Revisiting Temporal Evolution of Cu-Rich Precipitates in Fe–Cu Alloy: Correlative Small Angle Neutron Scattering and Atom-Probe Tomography Studies

“…Results from these different experimental techniques are largely in agreement with the CRP characteristics such as dimensions and number density. However, it may be noted that, among all these different experimental techniques, the small-angle scattering technique is particularly unique in its ability to provide statistically-averaged analysis over a wide range of length scales (typically 1–1,000 nm), making it very effective for such precipitation analysis in metallic systems (De Geuser & Deschamps, 2012; Biswas et al, 2016). The current study also focuses on temporal evolution of CRPs in the Fe–Cu system using the SANS technique, but in conjunction with APT.…”

Structural evolution and mechanism of strain glass transition in Ti48.7Ni51.3 shape memory alloy studied by anomalous small-angle X-ray scattering

“…The radial streaks in the 2D ASAXS patterns shown in Fig. 1 provide direct evidence of the plate-/disk-like morphology of the nanodomains 17,28,[35][36][37][38] . The corresponding 1D ASAXS profiles are shown in Fig.…”

“…Compared with the current structural characterization tools, synchrotron in-situ anomalous small-angle X-ray scattering (ASAXS) [22][23][24][25][26][27] with a tunable energy only sensitive to Ni atoms performed during a thermal cycle through T g may be the most effective or even a unique approach for solving the above challenges. Basically, SAXS allows quantitative studies of the size, geometry and spatial orientations of a number of nanoparticles in the bulk sample, as has been demonstrated in various alloys 26,[28][29][30][31][32][33][34] . In this study, the synchrotron in-situ ASAXS technique was performed during the thermal cycle (RT → T g → RT→ annealing temperature) of as-quenched Ti 48.7 Ni 51.3 specimens.…”

A Combinatorial Approach to Reliable Quantitative Analysis of Small Nano-Sized Precipitates: A Case Study with α′ Precipitates in Fe–20 at% Cr Alloy

“…More details about the analysis procedure can be found in Refs. (Biswas et al, 2011(Biswas et al, , 2014(Biswas et al, , 2016. The size, shape, number density, and volume fraction values are listed in Table 3.…”