The Mg99.2Zn0.2Y0.6 alloys were prepared by directional solidification, and the effect of loading modes on mechanical anisotropy and deformation mechanism of the alloys was studied. The microstructure of the alloy is columnar crystals whose growth orientations are mainly concentrated in <112(_)0>. When the tensile load is parallel to longitudinal grain boundaries of columnar crystals, the alloy has high yield strength (232 MPa), owing to basal <a> slip with hard orientation and {101(_)1} contraction twinning with high critical resolved shear stress (CRSS), but work hardening is not obvious. When the compressive load is parallel to longitudinal grain boundaries of columnar crystals, the alloy has high compressive strength (337 MPa) and good plasticity (maximum strain, 24 %), as well as distinct work hardening, which are related to (112(_)1) [112(_)6(_)] twins and good strain compatibility of grain boundaries. When the compressive load is perpendicular to longitudinal grain boundaries, the alloy shows high plasticity (maximum strain, 31 %) because the strip-like extension twins are parallel to the longitudinal grain boundaries during deformation.

中文翻译：

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具有特定取向柱状晶体的 Mg-Zn-Y 合金的机械各向异性


采用定向凝固法制备了 Mg99.2Zn0.2Y0.6 合金，研究了加载模式对合金力学各向异性和变形机理的影响。合金的微观组织为柱状晶体，其生长取向主要集中在 <112（_）0>。当拉伸载荷平行于柱状晶体的纵向晶界时，由于基底 <a> 滑移具有硬取向和具有高临界分辨剪切应力 （CRSS） 的 {101（_）1} 收缩孪晶，合金具有较高的屈服强度 （232 MPa），但加工硬化并不明显。当压缩载荷平行于柱状晶体的纵向晶界时，合金具有高抗压强度 （337 MPa） 和良好的塑性 （最大应变，24 %），以及明显的加工硬化，这与 （112（_）1） [112（_）6（_）] 孪晶有关，晶界的应变相容性好。当压缩载荷垂直于纵向晶界时，合金表现出高塑性（最大应变，31%），因为条状拉伸孪晶在变形过程中平行于纵向晶界。