Liu Rui, Tian Yanzhong, Zhang Zhenjun, An Xianghai, Zhang Peng, Zhang Zhefeng
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, P.R. China.
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia.
Sci Rep. 2016 Jun 6;6:27433. doi: 10.1038/srep27433.
It is commonly proposed that the fatigue strength can be enhanced by increasing the tensile strength, but this conclusion needs to be reconsidered according to our study. Here a recrystallized α-Cu-15at.%Al alloy with moderate grain size of 0.62 μm was fabricated by cold rolling and annealing, and this alloy achieved exceptional high fatigue strength of 280 MPa at 10(7) cycles. This value is much higher than the fatigue strength of 200 MPa for the nano-crystalline counterpart (0.04 μm in grain size) despite its higher tensile strength. The remarkable improvement of fatigue strength should be mainly attributed to the microstructure optimization, which helps achieve the reduction of initial damage and the dispersion of accumulated damage. A new strategy of "damage reduction" was then proposed for fatigue strength improvement, to supplement the former strengthening principle. The methods and strategies summarized in this work offer a general pathway for further improvement of fatigue strength, in order to ensure the long-term safety of structural materials.
人们普遍认为，通过提高抗拉强度可以增强疲劳强度，但根据我们的研究，这一结论需要重新考虑。在此，通过冷轧和退火制备了一种具有0.62μm中等晶粒尺寸的再结晶α-Cu-15at.%Al合金，该合金在10(7)次循环时达到了280MPa的异常高疲劳强度。尽管其抗拉强度较高，但该值远高于纳米晶对应物（晶粒尺寸为0.04μm）的200MPa疲劳强度。疲劳强度的显著提高应主要归因于微观结构优化，这有助于减少初始损伤并分散累积损伤。然后提出了一种“减少损伤”的新策略以提高疲劳强度，以补充先前的强化原理。这项工作中总结的方法和策略为进一步提高疲劳强度提供了一条通用途径，以确保结构材料的长期安全性。
