Manipulating deformation mechanisms with Y alloying of Mg
Manipulating deformation mechanisms with Y alloying of Mg
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DOI：
10.1016/j.msea.2021.141373
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
Jiaxiang Wang;Xin Wang;Kehang Yu;T. Rupert;S. Mahajan;E. Lavernia;J. Schoenung;I. Beyerlein
中科院分区：
文献类型：
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作者：
Jiaxiang Wang;Xin Wang;Kehang Yu;T. Rupert;S. Mahajan;E. Lavernia;J. Schoenung;I. Beyerlein
利用透射电镜、电子背散射衍射和粘塑性自洽多晶本构模型研究了Y含量对Mg-Y合金滑移和孪晶机制的影响。在热轧和再结晶板材中研究了四种浓度的Y。材料在轧制方向上的拉伸和压缩以及在法向方向上的压缩中变形，以便在每次测试中引起不同比例的滑移和孪晶机制。在多晶建模中使用的单晶硬化模型中，引入滑移-孪晶相互作用定律来解释由于孪晶界迁移过程中位错吸收引起的位错密度降低。我们发现，增加Y浓度降低了初始和变形纹理的强度。在变形过程中，屈服应力的塑性各向异性、拉压不对称性和10 1 <$2 <$1 <$0 11 <$孪晶的数量随着Y的增加而减少。对于每种合金，该模型确定了一组材料参数，成功地再现了所有测得的应力-应变曲线，并实现了与测得的变形织构和孪晶面积分数的协议。超越纹理的影响，模型解释的流动响应表明，Y的浓度增加的临界解析剪切应力的基础滑移，但对其他滑移模式的影响可以忽略不计。减少塑性各向异性与Y的增加是由伴随的棱柱体到金字塔形的滑移临界分辨剪应力比减少解释。该模型表明，它们几乎相等的临界分辨剪切应力值导致Mg-Y合金的非基础活性增强，这是由透射电子显微镜证实。计算表明，除了任何织构差异，这种减少在孪生可以归因于一个轻微增加的阻力为10 1 <$2 <$1 <$011 <$孪晶传播，特别是在二元最高Y含量。
The effect of Y concentration on the slip and twinning mechanisms in binary Mg–Y alloys are investigated using transmission electron microscopy, electron backscattered diffraction, and visco-plastic self-consistent polycrystal constitutive modeling. Four concentrations of Y are studied in hot-rolled and recrystallized sheet material. The materials were deformed in tension and compression in the rolling direction and compression in the normal direction in order to invoke distinct proportions of slip and twin mechanisms with each test. Within the single crystal hardening model used in polycrystal modeling, a slip-twin interaction law is introduced to account for dislocation density reductions due to dislocation absorption during twin boundary migration. We show that increasing Y concentration reduces the intensities of both the initial and deformation textures. During deformation, the plastic anisotropy in yield stress, the tension-compression asymmetry, and amount of 10 1‾ 2⟨ 1‾ 011⟩ twinning is shown to decrease with increasing Y. For each alloy, the model identifies a single set of material parameters that successfully reproduced all measured stress-strain curves and achieved agreement with measured deformation textures and twin area fractions. Transcending texture effects, the model interpretation of the flow responses suggests that increased concentrations of Y increase the critical resolved shear stress for basal slip but have negligible effects on the other slip modes. The reduced plastic anisotropy with increases in Y is explained by a concomitant decrease in the prismatic-to-pyramidal slip critical resolved shear stress ratio. The model suggests that their nearly equivalent critical resolved shear stress values lead to the enhanced non-basal activity of Mg–Y alloys, which was confirmed by transmission electron microscopy. The calculations suggest that beyond any texture differences, this reduction in twinning can be attributed to a slightly increased resistance for 10 1‾ 2⟨ 1‾ 011⟩ twin propagation, particularly in the binary with the highest Y content.