Abstract As a significant scientific problem directly impacting on the long-term safety of engineering materials and facilities, the improvement of fatigue strength under fully-reversed cycling was comprehensively explored in this study. Advantageous material characteristics for the improvement of fatigue strength were summarized from the achievements of the previous researches, followed by a new attempt to combine them in material design. As the model material, α-Cu-Al alloys with clean ultrafine-grains as well as large proportions of twin boundaries were thus produced, which exhibited a notable fatigue strength improvement (up to 155% higher than the coarse-grained counterparts and 40% higher than the counterparts produced by severe plastic deformation). Furthermore, a general principle briefly summarized as localized fatigue damage reduction was proposed based on the analysis of the optimizing methods including microstructure optimization and composition optimization. Accordingly, several recommended features to obtain such high fatigue strength materials were finally listed for further anti-fatigue design, such as uniform grains with small size and stable boundaries; low initial dislocation density, and proper alloying composition.

中文翻译：

---

探索提高Cu-Al合金疲劳强度

摘要 作为直接影响工程材料和设施长期安全的重大科学问题，本研究对全逆循环疲劳强度的提高进行了综合探索。从前人的研究成果中总结出有利于提高疲劳强度的材料特性，并在材料设计中进行了新的尝试。作为模型材料，由此生产出具有清洁超细晶粒和大比例孪晶界的 α-Cu-Al 合金，其疲劳强度显着提高（比粗晶合金高 155%，比粗晶合金高 40%）。高于严重塑性变形产生的对应物）。此外，在对微观组织优化和成分优化等优化方法进行分析的基础上，提出了一种简单概括为局部疲劳损伤减少的一般原则。因此，最终列出了获得这种高疲劳强度材料的几个推荐特征，以进行进一步的抗疲劳设计，例如均匀的晶粒、小尺寸和稳定的边界；初始位错密度低，合金成分合适。