This work aims to investigate the influence of solute segregation at particle-matrix interfaces on the twin activity of aged Mg alloys. With that purpose a binary Mg-8Al alloy (wt%) and two ternary Mg-8Al-1 Zn and Mg-8Al-1Ag alloys (wt%) were first homogenized and then aged in order to obtain comparable precipitate distributions. Particle-matrix interfaces in the binary alloy were observed to be clean, while Zn and Ag atomic segregation was clearly present at the interfaces of the ternary alloys. Room temperature micropillar compression tests were carried out in grains with favorable orientations for tensile twinning in the homogenized and the aged conditions for the three materials under investigation. The activation of twinning and slip was then characterized by electron microscopy. This study shows that while in the binary alloy precipitation did not lead to any major changes in the twinning activity and, in particular, it did not prevent the formation of thick twin lamellae encompassing the entire width of the tested micropillars, a drastic reduction of the twin activity took place in the aged ternary alloys. In the latter, straining led to the formation of narrow twin lamellae belonging to a single variant, and occasionally arrested at the interior of the micropillars. We propose that the drastic reduction of the twin volume fraction in the aged ternary alloys may be attributed to the decrease of the particle-matrix interface energy due to Zn and Ag segregation, which would hinder re-nucleation at such interfaces, thus suppressing twin propagation.

这项工作旨在研究颗粒-基体界面处溶质偏析对时效镁合金孪晶活性的影响。为此，首先对二元 Mg-8Al 合金 (wt%) 和两种三元 Mg-8Al-1 Zn 和 Mg-8Al-1Ag 合金 (wt%) 进行均质化处理，然后进行时效处理以获得可比较的沉淀物分布。观察到二元合金中的颗粒-基体界面是干净的，而三元合金的界面上明显存在 Zn 和 Ag 原子偏析。在研究中的三种材料的均质化和时效条件下，在具有拉伸孪晶有利取向的晶粒中进行了室温微柱压缩试验。然后通过电子显微镜表征孪生和滑移的激活。这项研究表明，虽然在二元合金中沉淀不会导致孪晶活性发生任何重大变化，特别是它不会阻止形成覆盖测试微柱整个宽度的厚孪晶薄片，但显着降低了双胞胎活动发生在老化的三元合金中。在后者中，应变导致形成属于单一变体的狭窄双薄片，偶尔会停在微柱的内部。我们提出，老化的三元合金中孪晶体积分数的急剧减少可能是由于 Zn 和 Ag 偏析导致颗粒-基体界面能降低，这将阻碍这些界面的再成核，从而抑制孪晶传播. 它并没有阻止形成覆盖整个测试微柱宽度的厚双薄片，在老化的三元合金中发生了双晶活性的急剧降低。在后者中，应变导致形成属于单一变体的狭窄双薄片，偶尔会停在微柱的内部。我们提出，老化的三元合金中孪晶体积分数的急剧减少可能是由于 Zn 和 Ag 偏析导致颗粒-基体界面能降低，这将阻碍这些界面的再成核，从而抑制孪晶传播. 它并没有阻止形成覆盖整个测试微柱宽度的厚双薄片，在老化的三元合金中发生了双晶活性的急剧降低。在后者中，应变导致形成属于单一变体的狭窄双薄片，偶尔会停在微柱的内部。我们提出，老化的三元合金中孪晶体积分数的急剧减少可能是由于 Zn 和 Ag 偏析导致颗粒-基体界面能降低，这将阻碍这些界面的再成核，从而抑制孪晶传播. 应变导致形成属于单一变体的狭窄双薄片，偶尔会停在微柱的内部。我们提出，老化的三元合金中孪晶体积分数的急剧减少可能是由于 Zn 和 Ag 偏析导致颗粒-基体界面能降低，这将阻碍这些界面的再成核，从而抑制孪晶传播. 应变导致形成属于单一变体的狭窄双薄片，偶尔会停在微柱的内部。我们提出，老化的三元合金中孪晶体积分数的急剧减少可能是由于 Zn 和 Ag 偏析导致颗粒-基体界面能降低，这将阻碍这些界面的再成核，从而抑制孪晶传播.