Micro-pillars of solution-treated and aged AZ91 magnesium alloy (Mg-9Al-0.7Zn-0.2Mn) have been used to study the influence of precipitates on plastic deformation mechanisms. The micro-pillars were compressed along $[55\overline{10}9]$ and $[01\overline{1}0]$ directions in order to activate basal slip and $\{01\overline{1}2\}$ twinning, respectively. The critical resolved shear stresses were determined. Precipitates had limited strengthening effect on basal slip, but increased significantly the stress required for twin growth. The precipitates are engulfed by the tension twins during deformation. The back stress generated due to the presence of the precipitates is expected to provide a considerable contribution to strengthening which slows the twin growth. A high density of stacking faults was observed in the aged specimen, particularly in between the precipitates, which may hinder dislocation glide upon further deformation.

固溶和时效处理的AZ91镁合金微柱（Mg-9Al-0.7Zn-0.2Mn）已用于研究沉淀对塑性变形机制的影响。微型支柱被压缩$[55\overline{10}9]$ 和 $[01\overline{\mathrm{1个}}0]$ 指示以激活基底滑移和 $\{01\overline{\mathrm{1个}}2\}$孪生。确定了临界解析剪切应力。沉淀物对基层滑移的增强作用有限，但显着增加了双生子生长所需的应力。在变形过程中，析出物被拉伸孪晶吞没。预计由于析出物的存在而产生的背应力将对强化产生相当大的作用，从而减慢孪晶的生长。在老化的试样中，尤其是在析出物之间，观察到了高密度的堆垛层错，这可能会阻止位错在进一步变形时滑移。