Thermally activated flow of dislocations in Al–Mg binary alloys

Niewczas, M.; Jobba, M.; Mishra, Raja K.

doi:10.1016/j.actamat.2014.09.056

Cited by 22 publications

(21 citation statements)

References 33 publications

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“…[1] and then further analyzed by Niewczas et al [2]. We show that the finitetemperature flow behavior of the alloys in these works can be explained by the inclusion of a low concentration of Fe without the need to invoke any other additional mechanisms.…”

Section: Introductionmentioning

confidence: 58%

“…However, such reasonable attempts to rationalize experimental data obfuscate the relevant underlying mechanisms. Here we re-examine recent data on a set of nominally binary Al-Mg alloys first reported by Jobba et al[1] and then further analyzed by Niewczas et al [2]. We show that the finitetemperature flow behavior of the alloys in these works can be explained by the inclusion of a low concentration of Fe without the need to invoke any other additional mechanisms.…”

mentioning

confidence: 70%

“…In more recent studies, Jobba et al have measured the yield stress of various Al-Mg alloys with concentrations ranging from 0.5-4.11% at 4 K, 78 K and 298 K at a strain ratė = 1.6 × 10 −4 [1,2]. We make comparisons between theory and experiments at 78 K and 298 K since dynamic effects occur at temperatures near 0K [18].…”

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confidence: 99%

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AbstractThe temperature-dependent flow behavior in nominally binary Al-Mg alloys measured recently [1,2] is interpreted in the context of a parameter-free solute strengthening model. The recent measurements show consistently higher strengths as compared to literature data on true binary Al-Mg alloys, which is attributed to the presence of Fe in the nominally binary Al-Mg.

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mentioning

confidence: 99%

“…For instance, HallPetch effects [2], anomalous athermal stresses [6], solute clustering [6,7], and/or unphysical dislocation/solute interactions [8][9][10], have been invoked to justify deviations between various solute strengthening theories [8][9][10][11][12] and experimental data. However, such reasonable attempts to rationalize experimental data obfuscate the relevant underlying mechanisms.…”

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confidence: 99%

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Thermally-activated flow in nominally binary Al–Mg alloys

Leyson

2016

Scripta Materialia

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The temperature-dependent flow behavior in nominally binary Al-Mg alloys measured recently [1,2] is interpreted in the context of a parameter-free solute strengthening model. The recent measurements show consistently higher strengths as compared to literature data on true binary Al-Mg alloys, which is attributed to the presence of Fe in the nominally binary Al-Mg. Using the Fe concentration as a single fitting parameter, the model predictions for the newer materials when treated as Al-Mg-(Fe) alloys agree with experiments to the same degree as obtained for the true binary Al-Mg. The model then predicts the activation volume in good agreement with experimental trends.In interpreting experimental data for strengths of Al alloys, multiple mechanisms operating simultaneously are often invoked because the application of simple or ad-hoc theories does not explain observed trends. For instance, HallPetch effects [2], anomalous athermal stresses [6], solute clustering [6,7], and/or unphysical dislocation/solute interactions [8][9][10], have been invoked to justify deviations between various solute strengthening theories [8][9][10][11][12] and experimental data. However, such reasonable attempts to rationalize experimental data obfuscate the relevant underlying mechanisms. Here we re-examine recent data on a set of nominally binary Al-Mg alloys first reported by Jobba et al.[1] and then further analyzed by Niewczas et al. [2]. We show that the finitetemperature flow behavior of the alloys in these works can be explained by the inclusion of a low concentration of Fe without the need to invoke any other additional mechanisms.The solute strengthening model was developed in Refs. [13,14] and only key points are summarized here. When moving through a random field of solutes with concentration c, an initially straight dislocation can lower its energy by bowing into regions containing favorable solute configurations and bowing away from regions with unfavorable solute configurations. The segments thus reside in favorable solute configurations and require stress-and thermally-driven activation to escape and move to the next favorable environment. The characteristic energy barrier ∆E b for pinned segments is ∆E b = 1.22

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Section: Introductionmentioning

confidence: 58%

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confidence: 70%

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confidence: 99%

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Thermally-activated flow in nominally binary Al–Mg alloys

Leyson

2016

Scripta Materialia

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Effect of Cr Content on Hot Deformation Behavior and Microstructure Evolution of Cu–Cr–Ni Bridge Weathering Steel

Xu,

Zhang,

Zhang

et al. 2024

steel research int.

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The hot compression tests (T = 850–1100 °C, = 0.1–10 s−1) of Cu–Cr–Ni bridge weathering steel with different Cr content (0.46% (#1), 0.64% (#2)) were performed on Gleeble‐3800‐D thermomechanical simulator. The effects of Cr content on hot deformation and microstructure evolution are systematically investigated by the Arrhenius constitutive equation, processing map, electron backscatter diffraction technology, and transmission electron microscope. In the results, it is demonstrated that the increase of Cr content from 0.46% to 0.64% enhances the solution strengthening and inhibits the dynamic recrystallization of the experimental steels during hot compression, resulting in the increase of flow stress. The Arrhenius constitutive equation with strain compensation is constructed. The increase of Cr content results in an augmentation of hot deformation activation energy, rising from Q#1 = 358.47 kJ mol−1 to Q#2 = 396.79 kJ mol−1, causing the increase of deformation resistance of Cu–Cr–Ni bridge weathering steel in hot compression. The optimal hot processing window of #1 and #2 experimental steels is as follows: = 0.1–0.2 s−1, T = 1050–1100 °C, = 0.1–0.15 s−1, and T = 1050–1100 °C, the increase of Cr content leads to the narrowing of the hot processing window of the experimental steels.

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