Effect of Cr on Microstructure and Mechanical Properties of Al–3.2Mg Alloys

Zhong, Zhao; Zhou, Ze Hua; Wang, Ze Hua; Zhang, Xin; Yuan, Huan; Xue, Xiao

doi:10.4028/www.scientific.net/amr.989-994.325

Cited by 2 publications

(1 citation statement)

References 18 publications

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“…Although direct methods of characterization, such as APT [40,41] and high-resolution transmission electron microscopy (HRTEM), [42] are advantageous, solid solutions have been examined by indirect methods as well. These include microhardness measurements, [43] X-ray diffraction analysis, [44,45] ultrasonic analysis, [46] calorimetric measurements, [47] electrical resistivity measurements, [48] and positron annihilation lifetime spectroscopy. [48] While the direct methods allow nanoscale resolution, HRTEM is limited to the examination of very small regions in 2D while APT allows the characterization of larger regions in 3D.…”

Section: Introductionmentioning

confidence: 99%

First‐Principles Design of Alloy Systems, Part I: Effects of Solute Type, Concentration, and Distribution on Alloying and Mechanical Properties – As‐Quenched Dilute Al (Mg, Si) Alloys

Samiee,

Shahmiri,

Sorrell

2023

Adv Eng Mater

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Solid solution strengthening is a well‐known strengthening mechanism for the 4xxx (Al‐Si alloys), 5xxx (Al‐Mg alloys), and 6xxx (Al–Mg–Si alloys). The distribution of solute atoms plays an important role in optimisation of the mechanical properties (increasing both the strength and ductility) of the alloys. While the distribution of solute atoms in the solid solution generally is assumed to be homogenous, solute clusters formed from randomly distributed solute atoms challenges this general assumption. Both dilute Al alloys (Al–Mg, Al–Si, and Al–Mg–Si) were solution treated at 450°C for 2 h and then quenched in room‐temperature water. They were analysed by atom probe tomography and these data have been employed in order to assess the 3D distribution of solute atoms in the solid solutions. The effects of the 3D distribution of solute atoms on the solid solution strengthening were also examined by mechanical testing (microhardness, tensile testing). An innovative approach was to abstain from conventional logic of binary vs ternary alloys in data analysis in favour of a less‐concentrated vs more‐concentrated strategy. This approach enables for the first time the integration of first principles Condon‐Morse atomic interaction effects, APT, and mechanical testing, which resulted in a novel empirical singleton‐cluster plot. The plot allows differentiation between singletons, solute clusters, and co‐clusters as well as between the less‐concentrated and more‐concentrated alloys. The plot also allows determination of the maximal yield strengths from cluster strengthening and from singletons in the absence of clustering. Most critically, this new approach in data analysis allows for the first time the determination of the d max based on experimental results. The APT statistical data analysis and the materials properties are underpinned by the newly identified differentiating roles of field, proximity, chemical, and atomic size effects on the distribution and homogeneity of the singletons and solute clusters. The singleton strengthening of the less concentrated dilute binary alloys is dominated by the field effect while cluster strengthening of the more concentrated dilute binary alloy inevitably is dominated by the proximity effect. In contrast, the co‐cluster strengthening of the less and more concentrated dilute ternary alloys involves a transition that is dependent largely on the dominance of the chemical effect over the proximity effect . A singular observation from these data is that the more concentrated dilute binary alloy exhibit simultaneous increases in both strength and ductility. Finally, the data for ductility and number densities of singletons and clusters suggests the dominant role of the proximity effect over that of the field and chemical effects.This article is protected by copyright. All rights reserved.

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