In situ observations of the kinetics of twinning–detwinning and dislocation slip in magnesium

Vinogradov, Alexei; Васильев, Е. В.; Linderov, Mikhail; Мерсон, Д. Л.

doi:10.1016/j.msea.2016.09.004

Cited by 35 publications

(22 citation statements)

References 43 publications

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“…The AE energy also drops at the point of loading reversal and remains low as long as the de-twinning process is active on the tensile part of each cycle. This finding is close to the results reported in [32,54,59], where it was argued that the de-twinning process, which is systematically observed at strain path reversal in Mg polycrystals, proceeds at the velocities much slower than those at twin nucleation and is not directly detectable by AE. This can be clearly seen on the enlarged fragment of the AE time-series shown in Figure 5b.…”

Section: Resultssupporting

confidence: 91%

“…This task is challenging yet tractable, since different AE sources generate different waveforms and therefore different Fourier power spectra at the sensor output. Applying the same ASK algorithm with a sliding window to the raw data acquired during cyclic deformation and grouping the frames with similar spectral features, allowed us to identify the signals corresponding to twinning in a way similar to that reported previously [32,54]. Figure 7 shows the results of the cluster analysis represented as the cumulative AE energy (a); and the average AE energy per cycle (b) separated for tensile and compressive stages.…”

Section: Resultsmentioning

confidence: 77%

“…The most prominent feature of the hysteresis loops observed is their asymmetry, which is often reported for Mg alloys due to the polar nature of mechanical twinning dominating the early deformation stage [53,54]. This asymmetry manifests itself in both the different stress amplitudes in tension and compression and in the different hardening behavior during tensile and compressive parts of the hysteresis loop.…”

Section: Resultsmentioning

confidence: 78%

“…The details of the particular features of the f m evolution in response to dislocation slip and twinning have been highlighted in [32] (cf. also [54,56]). One can notice that after the start of the test the AE spectral density shifts to a high frequency domain and the f m value increases sharply as is usually observed due to dislocation production and accumulation in fcc and bcc metals and alloys [56].…”

Section: Resultsmentioning

confidence: 88%

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Evolution of Mechanical Twinning during Cyclic Deformation of Mg-Zn-Ca Alloys

Vinogradov

Васильев

Linderov

et al. 2016

Metals

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Abstract:The present study clarifies the complex interplay between mechanical twinning and dislocation slip during low-cycle fatigue testing of Mg-Zn-Ca alloys. Temporal details of these mechanisms are studied non-destructively by in situ monitoring of the acoustic emission (AE) response powered by a robust signal categorization. Through the analysis of AE time series, the kinetics of deformation twinning per cycle and the overall accumulation of twinning during cyclic loading is described and its effect on fatigue life is highlighted.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 88%

See 2 more Smart Citations

Evolution of Mechanical Twinning during Cyclic Deformation of Mg-Zn-Ca Alloys

Vinogradov

Васильев

Linderov

et al. 2016

Metals

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“…For DIC measurements in fatigue investigations, images can be also obtained using electron microscopy for microscale observations . In this context, DIC has been shown to be useful at several scales to measure strain as a function of applied loading.…”

Section: Optical Nde Methods In Materials Fatiguementioning

confidence: 99%

The use of nondestructive evaluation methods in fatigue: A review

Wisner

Mazur

Kontsos

2020

Fatigue Fract Eng Mat Struct

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Efforts to understand fatigue in materials generally rely on defining relationships between the material response to fatigue loading and the evolving remaining material life portion. Typical measurements and data associated with such relationships include load (stress), displacement (strain), and associated properties (eg, mean stress and strain, energy dissipation, and residual stiffness). In addition to obtaining such measurements, efforts have been made to leverage nondestructive evaluation (NDE) methods to obtain additional information and enhance the description of the material fatigue response, especially its evolution due to interacting material‐microstructure‐property relationships. Given the range of available NDE methods and the number of materials they can be applied to, a critical overview of related investigations is presented in this article. Specifically, the state of the art of applying optical, thermal, acoustic, electromagnetic, X‐ray, and other diffraction NDE methods in fatigue investigations is provided and discussed. The methods are individually described for background and defining their relationship to fatigue, followed by descriptions of their current uses and contributions to enhancing the understanding of fatigue, and their limitations and ways that improvements could be made.

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Effect of Thermomechanical Treatment on Subsequent Deformation Behavior in a Binary Z1 Magnesium Alloy Studied by the Acoustic Emission Technique

et al. 2018

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Pre-straining of magnesium alloy modifies the final texture of the material and therefore leads to a different deformation behavior during subsequent loading. At the same time, heat treatment in the context of thermo-mechanical procedures is used as softening mechanism, as well as for age hardening processing. In mechanical conditions with twin-dominated deformation in textured magnesium alloys, the twin boundaries can be pinned if existing after a pre-deformation of samples and therefore influence their mobility. The impact of the ongoing mechanical behavior is discussed. In the present paper, a procedure of pre-compression and reverse tensile loading of extruded binary magnesium alloy Mg-1 wt% Zn (Z1) is used and intermediate aging at 200 C is applied in two different routes. The effect of the heat treatment on the flow behavior during subsequent mechanical loading is correlated with the dominating deformation mechanisms revealed by in situ acoustic emission measurements and ex situ scanning electron microscopy. The pinning of twin boundaries can restrict their mobility in experimental environments that favor the recovery of the samples. As a result, new twins easily nucleate if the concurrent re-orientation of the lattice is favorable for strain accommodation.

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In situ observations of the kinetics of twinning–detwinning and dislocation slip in magnesium

Cited by 35 publications

References 43 publications

Evolution of Mechanical Twinning during Cyclic Deformation of Mg-Zn-Ca Alloys

Evolution of Mechanical Twinning during Cyclic Deformation of Mg-Zn-Ca Alloys

The use of nondestructive evaluation methods in fatigue: A review

Effect of Thermomechanical Treatment on Subsequent Deformation Behavior in a Binary Z1 Magnesium Alloy Studied by the Acoustic Emission Technique

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