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 $\left\{10\bar{1}2\right\}⟨\bar{1}011⟩$ 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 $\left\{10\bar{1}2\right\}⟨\bar{1}011⟩$ twin propagation, particularly in the binary with the highest Y content.

使用透射电子显微镜，电子反向散射衍射和粘塑性自洽多晶体本构模型研究了Y浓度对Mg-Y二元合金中滑移和孪生机理的影响。在热轧和重结晶的片材中研究了四种浓度的Y。为了使每次测试都产生不同比例的滑移和孪生机制，材料在拉伸方向上的拉伸和压缩会发生变形，而在法线方向上会发生压缩。在多晶建模中使用的单晶硬化模型中，引入了滑移-孪生相互作用定律，以解释由于在双边界迁移过程中位错吸收而导致的位错密度降低。我们表明，增加Y浓度会降低初始纹理和变形纹理的强度。在变形过程中，塑性各向异性的屈服应力，拉伸-压缩不对称性和数量$\left\{10\stackrel{〜}{\mathrm{1个}}\mathrm{2个}\right\}⟨\stackrel{〜}{\mathrm{1个}}011⟩$结果表明，孪晶随着Y的增加而减少。对于每种合金，该模型都可以识别出一组材料参数，这些参数成功地再现了所有测得的应力-应变曲线，并与测得的变形织构和孪晶面积分数达成了一致。超越纹理效应，流动响应的模型解释表明，增加的Y浓度会增加基层滑移的临界解析剪切应力，但对其他滑移模式的影响可忽略不计。随着Y值的增加，塑性各向异性减小的原因是棱柱形至金字塔形滑移临界解析剪切应力比随之降低。该模型表明，它们几乎相等的临界解析剪切应力值导致Mg-Y合金的非基础活性增强，透射电子显微镜证实了这一点。计算表明，除了任何质地差异外，孪晶的这种减少可归因于抗拉强度的略微提高。$\left\{10\stackrel{〜}{\mathrm{1个}}\mathrm{2个}\right\}⟨\stackrel{〜}{\mathrm{1个}}011⟩$ 孪生传播，特别是在Y含量最高的二进制中。