This study investigates the effect of the deformation mode on the precipitation behavior of an extruded Mg–8.0Al–0.5Zn–0.2Mn (AZ80) alloy. The alloy samples are compared after the application of 3.5% tension and 3.5% compression along the extrusion direction to induce slip-dominant and twinning-dominant deformation modes, respectively. The pre-compressed (PC) sample, which contained numerous {10–12} tension twins, has a reduced grain size and a higher internal strain than the pre-tensioned (PT) sample, which is attributed to the inherent internal strain that occurs during the formation and growth of the twins. As a result, the precipitation behavior of the PC sample is accelerated, leading to its short peak aging time of 32 h, which is lower than those of the PT and as-extruded samples (48 and 100 h, respectively). Furthermore, fine continuous precipitates (CPs) rapidly form within the {10–12} twins, contributing to the enhanced hardness. Discontinuous precipitates (DPs), which have a hardness comparable to the CP-containing twinned regions, in the PC sample experience less coarsening during aging than those in the PT sample due to growth inhibition by the {10–12} twins. Ultimately, the {10–12} twins generated under the twinning-dominant deformation condition lead to enhanced precipitation behaviors, including the preferential formation and refinement of CPs and the suppressed coarsening of DPs. Consequently, pre-deformation that occurs {10–12} twinning exhibits more pronounced effects on precipitation acceleration and microstructural modification than slip-inducing pre-deformation.

中文翻译：

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预变形对 AZ80 合金析出行为的影响：滑移变形和孪晶变形的比较


本研究研究了变形模式对挤压 Mg–8.0Al–0.5Zn–0.2Mn （AZ80） 合金析出行为的影响。对沿挤压方向施加 3.5% 拉伸和 3.5% 压缩以分别诱导滑移主导和孪晶主导变形模式的合金样品进行了比较。预压缩 （PC） 样品包含许多 {10–12} 张力孪晶，与预紧 （PT） 样品相比，其晶粒尺寸更小，内部应变更高，这归因于孪晶形成和生长过程中发生的固有内部应变。结果，PC 样品的沉淀行为加速，导致其峰值老化时间短，为 32 小时，低于 PT 和挤出样品的峰值老化时间（分别为 48 小时和 100 小时）。此外，细小的连续沉淀物 （CP） 在 {10-12} 孪晶体内迅速形成，有助于提高硬度。由于 {10–12} 双胞胎的生长抑制，PC 样品中的不连续沉淀物 （DP） 的硬度与含 CP 的孪生区域相当，在老化过程中的粗化程度低于 PT 样品中的不连续沉淀物 （DP）。最终，在孪晶主导变形条件下生成的 {10–12} 孪晶导致沉淀行为增强，包括 CPs 的优先形成和细化以及 DPs 的抑制粗化。因此，与滑移诱导的预变形相比，发生的 {10–12} 双胞胎对降水加速和微观结构改性的影响更明显。