Extreme shear deformation is used for several material processing methods and is unavoidable in many engineering applications in which two surfaces are in relative motion against each other while in physical contact. The mechanistic understanding of the microstructural evolution of multi-phase metallic alloys under extreme shear deformation is still in its infancy. Here, we highlight the influence of shear deformation on the microstructural hierarchy and mechanical properties of a binary as-cast Al-4 at.% Si alloy. Shear-deformation-induced grain refinement, multiscale fragmentation of the eutectic Si-lamellae, and metastable solute saturated phases with distinctive defect structures led to a two-fold increase in the flow stresses determined by micropillar compression testing. These results highlight that shear deformation can achieve non-equilibrium microstructures with enhanced mechanical properties in Al–Si alloys. The experimental and computational insights obtained here are especially crucial for developing predictive models for microstructural evolution of metals under extreme shear deformation.

极限剪切变形用于几种材料加工方法，在许多工程应用中是不可避免的，在该应用中，两个表面在物理接触的同时彼此相对运动。对多相金属合金在极端剪切变形下的组织演变的机理了解仍处于起步阶段。在这里，我们重点介绍了剪切变形对二元态铸造的Al-4 at。％Si合金的组织结构和力学性能的影响。剪切变形引起的晶粒细化，共晶硅片的多尺度破碎以及具有独特缺陷结构的亚稳态溶质饱和相导致通过微柱压缩试验确定的流动应力增加了两倍。这些结果表明，剪切变形可以在Al-Si合金中获得具有增强的机械性能的非平衡微结构。此处获得的实验和计算见解对于开发在极端剪切变形下金属微结构演变的预测模型至关重要。