Effect of solute content and temperature on the deformation mechanisms and critical resolved shear stress in Mg-Al and Mg-Zn alloys

Wang, J.-Y.; Li, N.; Alizadeh, Reza; Monclús, M.A.; Cui, Yuchi; Molina-Aldareguía, J.M.; LLorca, J.

doi:10.1016/j.actamat.2019.03.027

Cited by 89 publications

(65 citation statements)

References 49 publications

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“…The CRSS values for twin nucleation and growth could be obtained from the stress-strain curves after careful examination of the deformation mechanisms and of the effect of micropillar size. This information, together with the CRSS for basal slip from a previous investigation [21] and for pyramidal slip obtained from micropillar compression tests along [0001], showed that the plastic anisotropy of Mg-Al alloys increased with the Al content.…”

Section: Introductionmentioning

confidence: 55%

“…The surfaces of the pure Mg and Mg-9 at.%Al discs were polished and diffusion-bonded in vacuum under a compression force of 800 N for 1 h at 673 K to create a Mg/Mg-9 at.%Al diffusion couple, which was annealed in Ar at 673 K during 352 h to obtain the composition gradient and release the thermal stresses. More details of the process to manufacture the diffusion couple can be found in [21].…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…It has been shown that the mechanical properties measured with square-section micropillars are equivalent to those obtained with circular ones [40]. It should be noted that ex situ micropillar compression tests were selected to analyse the mechanical behaviour instead of in situ tests [21] because the only additional information provided by the in situ tests (with respect to the ex situ tests) is the continuous imaging of the two external surfaces of the micropillar. But twin nucleation and growth may occur within the micropillar without modifying the observed external surfaces.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…These limitations can be overcome through the application of micromechanical testing techniques. In fact, micropillar compression tests have been extensively used to analyse the different deformation mechanisms of Mg and Mg alloys along specific orientations [17,21,26,[28][29][30][31][32][33][34][35], overcoming the limitations of tests in polycrystals. For instance, micropillar compression tests were performed in pure Mg along the a-axis [17,26,28,30,31,35] to explore the effect of the micropillar size on the mechanisms of {1012} twin deformation and on the CRSS for twin growth.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Al content on the critical resolved shear stress for twin nucleation and growth in Mg alloys

2020

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The effect of Al atoms in solid solution on the critical resolved shear stress for twin nucleation and growth was analyzed by means of the combination of diffusion couples with compression tests in micropillars oriented for twinning. The critical resolved shear stress for twin nucleation was higher than that for twin growth and both increased by the same amount with the Al content. Nevertheless, the increase was small (≈ 10 MPa) for 4 at.%Al but large (up to 60-70 MPa) for 9 at.%Al. These results were in agreement with Labusch-models based on first principles calculations in the dilute regime (< 5 at.%Al) [51]. Comparison with recent data in the literature showed that Al atoms are more effective in increasing the critical resolved shear stresses for twin nucleation and growth than for basal slip [21]. Finally, compression tests in micropillars oriented along [0001] showed the critical shear stress for pyramidal slip increased rapidly with the Al content from 98 MPa in pure Mg to 250 MPa in Mg-9 at.%Al. Thus, the addition of Al increased the plastic anisotropy of Mg alloys.

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Section: Introductionmentioning

confidence: 55%

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of Al content on the critical resolved shear stress for twin nucleation and growth in Mg alloys

2020

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“…Micropillars with an average aspect ratio in the range 2:1 to 3:1 were milled using a focus ion beam (FEI Helios NanoLab 600i) from the polycrystal in grains oriented single slip (the micropillar axis was close the <123> direction) using the methodology detailed in [25]. Micropillars of circular cross-section and different diameters (from 1 to 7 µm) as well as of square cross-section (5 × 5 µm 2 ) were carved to measure the CRSS in compression.…”

Section: Materials and Experimental Resultsmentioning

confidence: 99%

Multiscale modelling of precipitation hardening in Al–Cu alloys: Dislocation dynamics simulations and experimental validation

et al. 2020

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The mechanisms of dislocation/precipitate interactions were analyzed in an Al-Cu alloy containing a homogeneous dispersion of θ precipitates by means of discrete dislocation dynamics simulations. The simulations were carried out within the framework of the discrete-continuous method and the precipitates were assumed to be impenetrable by dislocations. The main parameters that determine the dislocation/precipitate interactions (elastic mismatch, stress-free transformation strains, dislocation mobility and cross-slip rate) were obtained from atomistic simulations, while the size, shape, spatial distribution and volume fraction of the precipitates were obtained from transmission electron microscopy. The predictions of the critical resolved shear stress (including the contribution of solid solution) were in agreement with the experimental results obtained by means of compression tests in micropillars of the Al-Cu alloy oriented for single slip. The simulations revealed that the most important contribution to the precipitation hardening of the alloy was provided by the stress-free transformation strains followed by the solution hardening and the Orowan mechanism due to the bow-out of the dislocations around the precipitates.

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Temperature Effect on Strain Hardening Behaviors of As‐Extruded Binary Magnesium Alloys

Zhao

Chen

et al. 2021

Adv Eng Mater

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Mg alloys, one of the lightest metallic structural materials, are used in many fields to reduce weight of components and parts due to their superior properties such as high specific strength and stiffness and favorable heat-resistance. [1,2] Despite all these advantages, the widespread application of Mg alloys was seriously prevented because of their poor ductility and RT-forming performance caused by limited slip systems and strong basal texture. [3][4][5] To enhance mechanical properties of Mg alloys, strain hardening, closely related to dislocation movement, comes into view. [6,7] Dislocation multiplication can be conducive to performance enhancement. Current researches paid attention mainly to effects of some parameters, such as grain size, twinning and second phase, on strain-hardening behaviors of Mg alloys. [8][9][10][11] However, service temperature, which can affect dislocation movement and accumulation of forest of dislocations, has a huge influence on critical resolved shear stress (CRSS) of slip systems. [12,13] Then, elevated temperature performance of some Mg alloys significantly decrease due to rapid loss of CRSS. Moreover, high-temperature deformation behaviors of Mg alloys may be influenced by diverse alloying elements. [14,15] The results from Jia et al. [16] and Yu et al. [17] also revealed that the mechanical properties for different alloys have different variation with the increase in temperature. Thus, it is necessary to carry out more researches about the effect of temperature on strain-hardening response to Mg alloys with various alloying elements.In this work, as-extruded Mg-3X (X ¼ Al, Zn, Sn, Y, and Gd) alloys were taken into consideration to investigate their strain-hardening behavior at room and elevated temperatures systematically. The work will be beneficial to analyze high-temperature deformation process in Mg alloys. Results Microstructure CharacterizationFigure 1 shows the XRD patterns and illustrates the phase composition of as-extruded Mg-3X. [5,7,10,18] The phase in Mg-3Al, Mg-3Zn, and Mg-3Y is α-Mg phase and there is no significant second phase in the α-Mg matrix, which indicates that the alloying elements are mainly dissolved in the matrix. In Mg-3Sn and Mg-3Gd, there is a small amount of second-phase precipitates, which are Mg 2 Sn and Mg 5 Gd, respectively. Figure 2a-e show the IPFs of these alloys with different alloying elements, which illustrate that fully dynamic recrystallization (DRX) occurs and uniform equiaxed grains are produced. Figure 2f shows the average grain size of Mg-3X alloys and conforms that grain-size refinement happened after extrusion treatment evidently. Average grain sizes of 21.8, 4.4, 12.6,and 10.5 μm, respectively. In addition to Mg-3Sn, the decreases in grain size of Mg-3X alloys are chiefly attributed to solute atoms pinning boundaries, and grain size of Mg-3Sn is also influenced by particle-stimulated

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Effect of solute content and temperature on the deformation mechanisms and critical resolved shear stress in Mg-Al and Mg-Zn alloys

Cited by 89 publications

References 49 publications

Effect of Al content on the critical resolved shear stress for twin nucleation and growth in Mg alloys

Effect of Al content on the critical resolved shear stress for twin nucleation and growth in Mg alloys

Multiscale modelling of precipitation hardening in Al–Cu alloys: Dislocation dynamics simulations and experimental validation

Temperature Effect on Strain Hardening Behaviors of As‐Extruded Binary Magnesium Alloys

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