A new strain rate dependent continuum framework for Mg alloys

García-Grajales, Julián A.; Fernández, Ana; Leary, Duncan; Jérusalem, Antoine

doi:10.1016/j.commatsci.2015.12.046

Cited by 14 publications

(4 citation statements)

References 98 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In current work, based on the available experimental results, the rate-dependent behaviours of magnesium alloys are studied by the crystal plasticity modelling considering different SRSs for different deformation mechanisms. As for the modeling, macroscopic continuum models are not suitable because different SRSs for multiple deformation mechanisms cannot be implemented (García-Grajales et al, 2016). The often-used crystal plasticity models to describe the mechanical response of polycrystalline materials include crystal plasticity finite element (Dawson et al, 2000(Dawson et al, , 2001Bronkhorst et al, 2007;Abdolvand et al, 2011;Wu et al, 2014;Qiao et al, 2015a), crystal plasticity-based Fast Fourier Transform (CP-FFT) models (Lebensohn et al, 2012) and mean-field effective-medium self-consistent (SC) models (Lebensohn and Tomé, 1993;Turner and Tomé, 1994;Wang et al, 2010c;2016c;.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Strain rate sensitivities of deformation mechanisms in magnesium alloys

Wang

Kurukuri

et al. 2018

International Journal of Plasticity

121

View full text Add to dashboard Cite

Strain rate sensitivity (SRS) is an important material property that governs the rate dependent mechanical behaviors associated with deformation rate changes, creep, stress relaxation, formability, etc. The variety of activated deformation mechanisms of magnesium alloys under different loading paths, e.g. tension vs. compression, implies that SRS of magnesium alloys obviously depends on loading paths, and each deformation mechanism has its own SRSs. However, a single SRS scheme is commonly employed in numerical modeling to describe the rate dependent behaviors of magnesium alloys, which disregards the distinction of SRSs among different deformation mechanisms. The implementation of the constitutive model that works for a wide range of values of SRSs has been a challenge to crystal plasticity modeling for metals with multiple deformation mechanisms like magnesium. Especially, very small values of SRS, corresponding to low rate-sensitivity, generally lead to high nonlinearity involved in the governing equations, and then computational failure. In this paper, the elasto-viscoplastic selfconsistent (EVPSC) crystal plasticity model is improved to enhance its numerical robustness for very small SRS values. Taking advantage of this improvement, different SRSs for various deformation mechanisms are employed to investigate the strain rate dependent behaviors of magnesium alloys at room temperature. First, the SRSs for various deformation mechanisms are determined based on the compressive stress relaxation tests on an AZ31 alloy plate; secondly, the obtained SRSs are applied to interpret internal elastic strain evolution of the same magnesium alloy under in-plane compression; finally, the determined SRSs are applied to investigate the deformation of another AZ31 alloy under various deformation paths and strain rates. The present work is the first effort on studying effects of strain rate-sensitivity on mechanical behavior of Mg alloys under wide range of applied strain rates by using an improved self-consistent polycrystal plasticity model. Good agreement between the experiments and simulations reveals the importance and necessity of using different SRSs for the deformation mechanisms involved. The rate dependent behaviors of magnesium alloys can be better described by using multiple SRSs associated to each operative deformation mechanism.

show abstract

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Strain rate sensitivities of deformation mechanisms in magnesium alloys

Wang

Kurukuri

et al. 2018

International Journal of Plasticity

121

View full text Add to dashboard Cite

show abstract

“…Due to a lack of easy slip deformation mechanisms and the c/a ratio, (10)(11)(12) extension twin is preferably activated by tension parallel to or compression perpendicular to c-axis [3]. A great deal of experimental and simulation studies have been conducted to understand the nature of twinning and detwinning and their effect on mechanical properties [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Grain Rotation during Twin-Detwin Deformation of Mg AZ31 Alloy Using <i>In Situ</i> XRD and EBSD

Zhang

Salvati

Papadaki

et al. 2019

KEM

View full text Add to dashboard Cite

To investigate grain rotation caused by twinning-detwinning during plastic deformation, experiments using synchrotron high energy X-ray Diffraction (XRD) and Electron Backscatter Diffraction (EBSD) are carried out under in situ compression-tension loading. Comparison between the XRD and EBSD data confirms that the intensity change of diffraction rings in XRD experiment is caused by twining and detwinning. A good agreement of twin fraction values obtained from XRD and EBSD is achieved. This demonstrates that the grains and texture are homogeneously distributed along the normal direction of the sample. In the meantime, it is observed that detwinning can only be activated in a large quantity when the loading reverses into tension from compression in the first loading stage.

show abstract

“…[44].While for cubic metals the same n value can be assigned for all slip systems [43,45], usually n value varies per slip mode for low symmetry metals, which deform by multiple slip modes [46]. For Mg, for instance, it is widely accepted that basal slip exhibits a very low strain rate sensitivity of approximately 10 -6 while prismatic and pyramidal slip have much higher values 0.0235 and 0.00742, respectively [47][48][49]. Low-symmetry metals also deform by deformation twinning, whose propagation is usually considered rate insensitive compared to slip [50].…”

mentioning

confidence: 99%

A numerical procedure enabling accurate descriptions of strain rate-sensitive flow of polycrystals within crystal visco-plasticity theory

Knežević

Zecevic

Beyerlein

et al. 2016

Computer Methods in Applied Mechanics and Engineering

View full text Add to dashboard Cite

The plastic deformation of polycrystalline metals is carried by the motion of dislocations on specific crystallographic glide planes. According to the thermodynamics theory of slip, in the regime of strain rates, roughly from 10 -5 /s to 10 5 /s, dislocation motion is thermally activated. Dislocations must overcome barriers in order to move, and this concept defines critical activation stresses on a slip system s that evolve as a function of strain rate and temperature. The fundamental flow rule in crystal visco-plasticity theory that involves in order to activate slip has a power-law form:. This form is desirable because it provides uniqueness of solution for the active slip systems that accommodate an imposed strain rate; however, it also introduces astrain rate dependence, which in order to represent the actual behavior of polycrystalline materials deforming in relevant conditions of temperature and strainrate usually needs to be describedby a high value of the exponent n. However, since until now the highest value of n was limited by numerical tractability, the use of the power-law flow rule frequently introduced an artificially high rate-sensitivity.All prior efforts tocorrect thisextraneous rate sensitivity have only lessened its effect and unfortunatelyalso at the expense of substantial increases in computation time. To this day, a solutionfor the power-law exponent reflecting true material behavior is still sought. This article provides a novel method enablingthe use of realistic material strain rate-sensitivity exponents to be used within the crystal vico-plasticity theory without increasing computation time involved in polycrystal simulations. Calculations are performed for polycrystalline pure Cu and excellent agreement with experimental measurement is demonstrated.

show abstract

A new strain rate dependent continuum framework for Mg alloys

Cited by 14 publications

References 98 publications

Strain rate sensitivities of deformation mechanisms in magnesium alloys

Strain rate sensitivities of deformation mechanisms in magnesium alloys

Grain Rotation during Twin-Detwin Deformation of Mg AZ31 Alloy Using <i>In Situ</i> XRD and EBSD

A numerical procedure enabling accurate descriptions of strain rate-sensitive flow of polycrystals within crystal visco-plasticity theory

Contact Info

Product

Resources

About