The inherent hexagonal close-packed (HCP) structure of magnesium (Mg) alloys leads to anisotropy in their deformation mechanism. In this study, the deformation behavior of Mg-2Y alloys with varying grain orientations was investigated by using nanoindentation experiments coupled with Electron Back Scatter Diffraction (EBSD) and Crystal Plasticity Finite Element Method (CPFEM) techniques. It has been found that “Hard grains” demonstrate significantly higher hardness and elastic modulus compared to “Soft grains”. This distinction is primarily attributed to the varying Schmid factors of the slip systems corresponding to different grain orientations, resulting in the anisotropy of deformation mechanism. The dominant deformation mechanism for “Hard grains” is basal slip, while prismatic and pyramidal slip dominate for “Soft grains”. The activation of the corresponding slip system was confirmed by the in-grain misorientation axes (IGMA) distribution, indentation surface morphology, slip trace analysis, and CPFEM simulations. Additionally, fixed-target grain boundary indentation experiments and geometrical compatibility calculations were employed to determine that the effect of grain boundaries on plastic deformation mechanism is primarily dependent on the neighboring grains misorientation angle. The mechanism of competitive and coordinated behaviors between deformation mechanisms was also revealed.

中文翻译：

---

使用纳米压痕和 CPFEM 研究 Mg-2Y 中晶内和晶界变形行为的取向依赖性


镁合金固有的六方密排（HCP）结构导致其变形机制的各向异性。在这项研究中，通过纳米压痕实验结合电子背散射衍射（EBSD）和晶体塑性有限元法（CPFEM）技术研究了不同晶粒取向的Mg-2Y合金的变形行为。研究发现，与“软颗粒”相比，“硬颗粒”表现出明显更高的硬度和弹性模量。这种区别主要归因于不同晶粒取向对应的滑移系统的施密德因子不同，导致变形机制的各向异性。 “硬晶粒”的主要变形机制是基底滑移，而“软晶粒”的主要变形机制是棱柱形和金字塔形滑移。通过晶内取向差轴 (IGMA) 分布、压痕表面形态、滑移轨迹分析和 CPFEM 模拟证实了相应滑移系统的激活。此外，采用固定目标晶界压痕实验和几何兼容性计算来确定晶界对塑性变形机制的影响主要取决于相邻晶粒的取向差角。还揭示了变形机制之间竞争和协调行为的机制。