Formulation of initial artificial age-hardening response in an Al-Mg-Si alloy based on the cluster classification using a high-detection-efficiency atom probe

Clustering in Age‐Hardenable Aluminum Alloys

“…Long term NA leads to higher volume fraction of Si-rich clusters, which are concluded to be the critical constituent for the occurrence of the negative effect. [102] We conclude: 1) Clusters formed during NA and clusters formed during PA are possibly two different kinds of clusters. 2) PA forms Mg, Si co-clusters which act as nucleation site or can transform into β 00 during AA.…”

“…The two-dimensional detectors have usually a detection efficiency of %37 to %57%, though most recent developments have improved detectors (as in the Cameca LEAP 5000) up to 80%. [102] Therefore, only a fraction of the atoms of the original sample are pictured in the reconstruction. This is especially crucial for small sized features such as clusters.…”

“…Often the protocol based on a modified stereographic projection is used for the reconstruction, [109] here the two parameters (namely the image compression factor and the field factor times the evaporation field) can be used to tune the reconstruction, so that the inter-planar distances in the atom map fit to the real inter-planar distances. [110,111] It should be noted that there are large and ongoing efforts being made to increase the accuracy of the reconstruction algorithm, [102] recently also revisiting a different projection model [112] or building the reconstruction in a reverse manner and calculating the ion trajectories. [113] Distorted or bad reconstructions would affect cluster analysis in shape or absolute size analysis, and worsen comparability in between different measurements.…”

“…Selecting parameters based upon establishing the least conservative parameter values that resulted in no "random" clusters being found in a random labelled version of the original APT data. [62,102,[130][131][132][133][134][135] Other more elaborate approaches using randomized datasets to generate various heuristic metrics have been developed [136][137][138] but could be considered as less than physical so caution must be employed to at least apply these consistently.…”

“…[130,131] Latest research compares the findings on NA and PA between the newly available high detection efficiency atom probe (LEAP 5000 XS) and atom probe data generated by lower detection efficiency (LEAP 3000 HR) for an excess Si alloy (see Table 3). [102] Generally, a shift to larger cluster sizes, in the plot number density over Guinier radius, is obtained for a high detection efficiency atom probe. Also the average Mg/(Mg þ Si) ratio is found slightly increased with higher detection efficiency.…”