The grain-scale tension-compression (T-C) asymmetric slip behavior and geometrically necessary dislocation (GND) density in an aged and twin-free Mg-10Y sheet were statistically studied using slip trace analysis and electron backscatter diffraction (EBSD) analysis. A significantly asymmetric slip activity, i.e., higher tensile slip activity and proportion of non-basal slip, was manifested. Prismatic 〈a〉 (37.1 %) and basal 〈a〉 (27.6 %) slips dominated the tensile deformation, followed by pyramidal II 〈c + a〉 slip (20.0 %). While during compression, basal 〈a〉 slip (61.9 %) was the most active slip mode, and only 6.9 % pyramidal II 〈c + a〉 slip was observed. The critical resolved shear stress (CRSS) ratio was estimated based on ∼800 sets of the identified slip traces, which suggested that the CRSS_{pyr II}/CRSS_bas for compression was ∼3 times than that of tension. The pyramidal II 〈c + a〉 slip was more active when the slip plane was under tension than under compression, which was consistent with the calculated asymmetric CRSS_{pyr II}/CRSS_bas. The activity of multiple slip, cross slip and slip transfer, as well as the GND density were also T-C asymmetric. This work thoughtfully demonstrated the T-C asymmetric slip behavior and plastic heterogeneity in Mg alloys which was believed to be responsible for the macroscopic T-C asymmetry when twinning was absent. The present statistical results are valuable for validating and/or facilitating crystal plasticity simulations.

中文翻译：

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老化 Mg-10Y 片材滑移行为和塑性异质性拉伸-压缩不对称性的统计研究


使用滑移轨迹分析和电子背散射衍射 （EBSD） 分析对老化且无孪晶的 Mg-10Y 片材中的晶粒尺度拉伸压缩 （T-C） 不对称滑移行为和几何必要位错 （GND） 密度进行了统计研究。表现出显著不对称的滑移活性，即较高的拉伸滑移活性和非基底滑移的比例。棱柱形〈a〉（37.1 %）和基部〈a〉（27.6 %）滑移在拉伸变形中占主导地位，其次是金字塔形II〈c+a〉滑移（20.0 %）。而在压缩过程中，基底 〈a〉 滑移 （61.9 %） 是最活跃的滑移模式，仅观察到 6.9 % 的锥体 II 〈c + a〉 滑移。临界分辨剪切应力 （CRSS） 比是根据 ∼800 组已识别的滑动轨迹估计的，这表明压缩的 CRSS_{pyr II}/CRSS_bas 是拉伸的 ∼3 倍。当滑移面处于拉伸状态时，金字塔 II 〈c + a〉 滑移比在压缩下更活跃，这与计算的不对称 CRSS_{pyr II}/CRSS_bas 一致。多次滑移、交叉滑移和滑移的活性以及 GND 密度也是 T-C 不对称的。这项工作深思熟虑地证明了 Mg 合金中的 T-C 不对称滑移行为和塑性不均匀性，这被认为是在没有孪晶时宏观 T-C 不对称性的原因。目前的统计结果对于验证和/或促进晶体塑性模拟很有价值。