In this study, a high-strength Al–11Si alloy with an improved ductility was developed via a two-step processing route - equal-channel angular pressing (ECAP) and post-cryorolling. Specifically, the cast alloy was ECAP processed at 623 K for 16 passes, followed by multi-pass cryorolling with 50% thickness reduction. Herein, its mechanical properties was evaluated, and the underlying mechanisms for the improvement of both strength and ductility was investigated. Through systematic comparisons with other samples, including the cast, the cast-rolled, the ECAP-processed and the ECAP-annealed samples, we found the respective origin for the high strength and the improved ductility in the processed alloy. On the one hand, the high strength resulted from both grain boundary strengthening and dislocation strengthening caused by the thermo-mechanical processing. On the other hand, the improved ductility was primarily dictated by the uniform distribution of the very fine Si particles due to the attendant fragmentation of the Si phase during ECAP process. In addition, the results showed that the superior combination of strength and ductility could not be achieved by either processing step alone. This two-step processing route is also promising to benefit other Al–Si alloys for structural applications by optimizing their mechanical properties.

在这项研究中，通过两步工艺路线（等通道角压（ECAP）和后冷轧）开发了具有改善的延展性的高强度Al-11Si合金。具体而言，对铸造合金进行623 K的ECAP处理16道次，然后进行多道次冷轧，厚度降低50％。在此，评估其机械性能，并研究改善强度和延展性的基本机理。通过与包括铸造，铸造轧制，ECAP加工和ECAP退火的其他样品的系统比较，我们找到了加工合金的高强度和改善的延展性的各自来源。一方面，高强度是由热机械加工引起的晶界强化和位错强化共同产生的。另一方面，延展性的提高主要是由于在ECAP过程中伴随着Si相的碎裂而导致的非常细的Si颗粒的均匀分布所决定的。另外，结果表明，仅通过任一加工步骤都不能实现强度和延展性的优异组合。这种两步加工路线也有望通过优化其机械性能，使其他Al-Si合金在结构应用中受益。结果表明，仅通过任何一个加工步骤都无法实现强度和延展性的优异组合。这种两步工艺路线还有望通过优化其机械性能，使其他Al-Si合金在结构应用中受益。结果表明，仅通过任何一个加工步骤都无法实现强度和延展性的优异组合。这种两步加工路线也有望通过优化其机械性能，使其他Al-Si合金在结构应用中受益。