An Orowan precipitate strengthening equation for mechanical twinning in Mg

Barnett, Matthew; Wang, Huan; Guo, Tingting

doi:10.1016/j.ijplas.2018.08.010

Cited by 72 publications

(18 citation statements)

References 64 publications

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“…In contrast, twin-precipitate interactions are more complex and less understood. This has attracted significant attention of material research at the present time [10][11][12][13][14][15][16]. For instance, the effect of precipitation on yield elongation in an extruded Mg-4.5 wt% Zn alloy was investigated in [10].…”

Section: Introductionmentioning

confidence: 99%

“…Twins in the as-extruded sample were thicker and fewer in number than those in the aged sample. Applicability of the Orowan precipitate hardening equation to twin propagation was studied in [11] by two-dimensional dislocation dynamics simulations of a twin tip impinging upon a line of obstacles. It was shown that reasonable prediction of propagation stress can occur.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of Migrating Twin Boundaries with Obstacles in Magnesium

Ostapovets

Kushnir

Máthis

et al. 2021

Metals

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Interaction of migrating {101¯2} twin boundary with obstacles was analyzed by atomistic and finite elements computer simulations of magnesium. Two types of obstacles were considered: one is a non-shearable obstacle and another one is the void inside bulk material. It is shown that both types of obstacles inhibit twin growth and increased stress is necessary to engulf the obstacle in both cases. However, the increase of critical resolved shear stress is higher for the passage of the twin boundary through raw of voids than for interaction with non-shearable obstacles.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interaction of Migrating Twin Boundaries with Obstacles in Magnesium

Ostapovets

Kushnir

Máthis

et al. 2021

Metals

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“…In 2018, Robson and Barnett pointed out in a review that an equivalent simple equation to the BKS model predicting the strengthening effect of precipitates against twins would be very useful, but the physical basis for such an equation remains unclear [17]. In 2019, an Orowan precipitate hardening equation specifically applicable to twin propagation was developed [23]. A scenario of TDs piling-up and bowing at a line of non-shearable obstacles was adopted to modify the BKS model of Orowan stress calculation by the TD number, n. In the same year, the effective planar interparticle spacing L and the mean planar diameter of the particles on the twinning plane D in the BKS model were also adjusted according to experimental results [20].…”

Section: Introductionmentioning

confidence: 99%

The Orowan Stress Measurement of Twinning Dislocations in Magnesium

Tang

Guo

2021

Metals

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The interaction between a lattice dislocation and non-shearable precipitates has been well explained by the Orowan bypass mechanism. The calculated additional shear stress facilitates the evaluation of precipitation hardening in metallic alloys. The lack of information about how a twinning dislocation behaves in the same scenario hinders our understanding of the strengthening against twin-mediated plasticity in magnesium alloys. In the current study, the bowing and bypassing of a twining dislocation impeded by impenetrable obstacles are captured by atomistic simulations. The Orowan stress measurement is realized by revealing the stick-slip dynamics of a twinning dislocation. The measured Orowan stress significantly deviate from what classic theory predicts. This deviation implies that the line tension approximation may generally overestimate the Orowan stress for twinning dislocations.

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“…Grain-size reduction, precipitation strengthening, and texture weakening are all proven to be effective in decreasing yield asymmetry between tension and compression [10][11][12]16,19,[25][26][27][28][29][30][31][32][33][34][35][36][37]. For instance, Barnett et al [16] found that the grain size affects yield stress and the sensitivity of twinning to grain size is obviously bigger than that of the slip.…”

Section: Introductionmentioning

confidence: 99%

Reducing Yield Asymmetry between Tension and Compression by Fabricating ZK60/WE43 Bimetal Composites

Zhao

Song

et al. 2020

Materials

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In this study ZK60/WE43 bimetal composite rods were manufactured by a special method of hot diffusion and co-extrusion. Interface microstructure, deformation mechanism, and yield asymmetry between tension and compression for the composite rods were systematically investigated. It was observed that the salient deformation mechanism of the ZK60 constituent was {10-12}<−1011> extension twinning in compression and prismatic slip in tension, and different deformation modes resulted in yield asymmetry between tension and compression. In contrast, the WE43 constituent tends to be more isotropic due to grain refinement, texture weakening, solid-solution and precipitation strengthening, which were deformed via basal slip, prismatic slip, and {10-12}<−1011> extension twinning in both tension and compression. Surprisingly, it was found that yield asymmetry between tension and compression for the ZK60/WE43 composite rods along the extrusion direction was effectively reduced with a compression-to-tension ratio of ~0.9. The strongly bonded interface acting as a stress transfer medium for the ZK60 sleeve and WE43 core exhibited the coordinated deformation behavior. This finding provides an effective method to decrease the yield asymmetry between tension and compression in the extruded magnesium alloys.

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An Orowan precipitate strengthening equation for mechanical twinning in Mg

Cited by 72 publications

References 64 publications

Interaction of Migrating Twin Boundaries with Obstacles in Magnesium

Interaction of Migrating Twin Boundaries with Obstacles in Magnesium

The Orowan Stress Measurement of Twinning Dislocations in Magnesium

Reducing Yield Asymmetry between Tension and Compression by Fabricating ZK60/WE43 Bimetal Composites

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