Effect of the loading mode on the evolution of the deformation mechanisms in randomly textured magnesium polycrystals – Comparison of experimental and modeling results

Máthis, Kristián; Csiszár, Gábor; Čapek, Jan; Gubicza, Jenő; Clausen, B.; Lukáš, P.; Vinogradov, Alexei; Agnew, Sean R.

doi:10.1016/j.ijplas.2015.05.009

Cited by 93 publications

(62 citation statements)

References 86 publications

(123 reference statements)

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“…In HCP alloys there are slip systems with both different Burgers vectors (<a> and <c+a>), and different slip planes (basal, prismatic and pyramidal). The homogeneous approach, as outlined by Dragomir and Ungar [30] and based on Equation (3), has been used in a number of works to evaluate the slip activity of different Burgers vector types [85][86][87][88][89][90][91][92]. However, because of the difficulty in quantifying the dislocation types in HCP alloys, corroborating characterisation test results to verify the approach is problematic.…”

Section: Homogeneous Approachmentioning

confidence: 99%

“…The second approach (Figure 18d) is a slight modification to the previous one, whereby the available slip system types are reduced to those expected to be the most important types in titanium [83]. This type of approach, involving reducing the available slip systems has been used by different authors [31,85]. These approaches are generally only used to predict the quantity of different Burgers vector types, <a>, <c+a> and <c>; although Mathis et al [85] also used the approach to find the relative quantity of two different slip system types, prismatic and basal <a>.…”

Section: Homogeneous Approachmentioning

confidence: 99%

“…This type of approach, involving reducing the available slip systems has been used by different authors [31,85]. These approaches are generally only used to predict the quantity of different Burgers vector types, <a>, <c+a> and <c>; although Mathis et al [85] also used the approach to find the relative quantity of two different slip system types, prismatic and basal <a>. The reason for this is that using two variables (q 1 and q 2 ) to find details of any more than three parameters is impractical because there are too many possible combinations.…”

Section: Homogeneous Approachmentioning

confidence: 99%

“…vector types, <a>, <c+a> and <c>; although Mathis et al [85] also used the approach to find the relative quantity of two different slip system types, prismatic and basal <a>. The reason for this is that using two variables (q1 and q2) to find details of any more than three parameters is impractical because there are too many possible combinations.…”

Section: Homogeneous Approachmentioning

confidence: 99%

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Peak Broadening Anisotropy and the Contrast Factor in Metal Alloys

Simm

2018

Crystals

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Diffraction peak profile analysis (DPPA) is a valuable method to understand the microstructure and defects present in a crystalline material. Peak broadening anisotropy, where broadening of a diffraction peak doesn't change smoothly with 2θ or d-spacing, is an important aspect of these methods. There are numerous approaches to take to deal with this anisotropy in metal alloys, which can be used to gain information about the dislocation types present in a sample and the amount of planar faults. However, there are problems in determining which method to use and the potential errors that can result. This is particularly the case for hexagonal close packed (HCP) alloys. There is though a distinct advantage of broadening anisotropy in that it provides a unique and potentially valuable way to develop crystal plasticity and work-hardening models. In this work we use several practical examples of the use of DPPA to highlight the issues of broadening anisotropy. of 31where, D is the crystal size, K Sch is the Scherrer constant (often taken as 0.9 for spherical crystals), g is the reciprocal of the d-spacing of a peak, f m is a function related to the arrangement of dislocations (and represents how the arrangement of groups of dislocations influence their total strain), ρ is the dislocation density and C hkl is the average contrast factor of dislocations in grains that contribute to the hkl diffraction peak. In Equation 1 and other DPPA approaches, C hkl is assumed to be the only term that accounts for broadening anisotropy and its value is required to be able to obtain the dislocation density.TEM to be able to identify details of dislocations [15,16], especially in cases when g.b=0 does not lead to vanishing contrast or due to practicalities of rotating a sample. In the same manner, the diffraction broadening caused by a dislocation varies depending on the diffraction vector, and can be calculated by modelling the dislocation's displacement field. The contribution of a dislocation's displacement field to the broadening of different diffraction profiles is through what is known as the contrast (or orientation) factor of dislocations. The contrast factor of an individual dislocation is dependent on the angles between the diffraction vector and the vectors that define the dislocation: it's Burgers vector (b), slip plane normal (n), and dislocation line (s). The contrast factor of an individual dislocation can be calculated using the computer program ANIZC [17]. For example, the edge dislocation in Figure 2 has a contrast factor of 0.46 when g is [110] and parallel to the dislocations Burgers vector. The value is 0.00 when g is parallel to the slip line ([11 2]) and 0.05 when g is parallel to the slip plane normal ([1 11]).

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Section: Homogeneous Approachmentioning

confidence: 99%

Section: Homogeneous Approachmentioning

confidence: 99%

Section: Homogeneous Approachmentioning

confidence: 99%

Section: Homogeneous Approachmentioning

confidence: 99%

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Peak Broadening Anisotropy and the Contrast Factor in Metal Alloys

Simm

2018

Crystals

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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

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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