An integrated experimental and microstructure-based simulation research was carried out to study the effect of thickness and grain size on the mechanical response and deformation mechanism of AZ31 Mg foils. Equal channel angle pressing (ECAP) and subsequent annealing were applied to fabricate the billets with tailored microstructures. Ex situ micro-tensile tests of the foils were conducted to explore the meso-scale size effect. The experimental results show that the flow stress, ductility, and microstructure evolution of the foils are significantly affected by both grain size and thickness. With the increase of grain number (λ) in thickness, the flow stress curve changes from convex-up to a typical sigmoidal shape, and the extension twinning is remarkably suppressed. Full-field crystal plasticity simulations successfully captured the micromechanical interaction between dislocation slip and twinning. Specifically, the decrease of λ enhances the dominance of extension twinning on the mechanical response and ductility of the foils and further intensifies the interaction of deformation twinning on slip resistance. As a measurement for describing the combined effect of grain size and geometrical size, λ is a critical factor affecting the interaction and competition between dislocation slip and deformation twinning.

为了研究厚度和晶粒尺寸对 AZ31 镁箔的机械响应和变形机制的影响，进行了基于实验和微观结构的综合模拟研究。应用等通道角压制 (ECAP) 和随后的退火来制造具有定制微结构的坯料。对箔进行了非原位微拉伸试验以探索中尺度尺寸效应。实验结果表明，箔的流动应力、延展性和微观结构演变受晶粒尺寸和厚度的显着影响。随着晶粒数的增加（λ) 在厚度上，流变应力曲线由凸形变为典型的 sigmoidal 形，拉伸孪晶得到显着抑制。全场晶体塑性模拟成功地捕获了位错滑移和孪晶之间的微机械相互作用。具体而言，λ的减小增强了拉伸孪生对箔的机械响应和延展性的主导作用，并进一步加强了变形孪生对滑动阻力的相互作用。作为描述晶粒尺寸和几何尺寸组合效应的度量，λ是影响位错滑移和形变孪晶相互作用和竞争的关键因素。