Effect of grain size on the mechanisms of plastic deformation in wrought Mg–Zn–Zr alloy revealed by acoustic emission measurements

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Abstract:Fatigue properties under axisymmetric push-pull loading of a magnesium alloy Mg-6Zn-0.5Zr (ZK60) after processing by multiaxial isothermal forging (MIF) to a total strain of 4.2 at 400 °C were investigated. The strong influence of the microstructure on the mechanical behavior is demonstrated. Hot severe plastic deformation was shown effective in improving the fatigue life in both the high-and low-cyclic regimes.

Section: Resultsmentioning

confidence: 90%

Fatigue Performance of Mg-Zn-Zr Alloy Processed by Hot Severe Plastic Deformation

Васильев

Linderov

Nugmanov

et al. 2015

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“…A novel statistical method of AE signal categorization and recognition developed in [25] has been proven effective for real-time analysis of elementary deformation mechanisms in advanced materials including Mg alloys. The method was successfully tested and applied for discrimination between contributing deformation mechanisms such as dislocation slip, twinning and martensitic transformations from the AE signal at various stages of deformation in several materials [26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

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

Vinogradov

Васильев

Linderov

et al. 2016

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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.

“…As has been suggested in [14] and then probed in several studies on different materials [18][19][20], satisfactory results of clustering are obtained if the if the Kullback-Leibler divergence (KL) in its symmetric version is used as the distance measure ||•|| 2 as…”

Section: Ae Data Analysismentioning

confidence: 94%

Acoustic Emission Assessment of Impending Fracture in a Cyclically Loading Structural Steel

Растегаев

Danyuk

Afanasyev

et al. 2016

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Using the advanced acoustic emission (AE) technique, we address the problem of early identification of crack initiation and growth in ductile structural steels under cyclic loading. The notched 9MnSi5 steel specimens with weld joints were fatigue tested at room and lower temperatures with concurrent AE measurements. Detection of AE in ductile materials where fatigue crack initiation and propagation is mediated by local dislocation behavior ahead of the notch or crack tip is challenging because of an extremely low amplitude of the AE signal. With account of this issue, two new practically oriented criteria for recognition of different stages of fatigue are proposed on the basis of AE data: (1) a power spectrum-based criterion and (2) a pattern recognition-based criterion utilizing modern clustering algorithms. The applicability of both criteria is verified using obtained AE data. A good correspondence between AE outcomes and experimental observations of the fatigue behavior was obtained and is discussed.