Effect of grain structure on fatigue crack propagation behavior of Al-Cu-Li alloys  

作　　者：Dingding Lu Ben Lin Tianle Liu Sanxi Deng Youjie Guo Jinfeng Li Danyang Liu 

机构地区：[1]School of Materials Science and Engineering,Central South University,Changsha 410083,China [2]China Academy of Launch Vehicle Technology,Beijing 100076,China [3]State Key Laboratory of Nonferrous Metals and Processes,GRINM Group Co.,LTD.,Beijing 100088,China [4]Key Laboratory of Nonferrous Metal Materials Science and Engineering,Ministry of Education,Changsha 410083,China

出　　处：《Journal of Materials Science & Technology》2023年第17期75-89,共15页材料科学技术（英文版）

摘　　要：Recrystallization behavior during optimized heat treatments provides a potential to obtain desirable grain structure,which significantly improves the mechanical properties of aluminum alloys.The influence of grain structures on fatigue crack propagation(FCP)behaviors of Al-Cu-Li alloy with hot-rolled(HR)and cold-rolled(CR)was investigated.Subgrain boundaries have a significant impact on small crack growth rates,which is reflected in the pronounced fluctuation of fatigue crack growth of HR specimens after solution treatment.Moreover,the specific cellular structure within grains can improve the deformation capacity of alloys due to their accommodation of plastic deformation,which contributes to the lower fatigue crack growth rates and higher threshold values in HR specimens.The intragranular deflection also decelerates the FCP rate and occurs in these regions of large grain without subgrain boundaries.Recrystallization occurs in the CR specimens,resulting in small anisotropy on the fatigue resistance for the different orientations in the Paris stage due to the recrystallization texture.Fatigue cracks can be deflected and tend to propagate along the grain boundaries when it goes into the grain with a relatively low Schmidt factor value.

关 键 词：Al-Cu-Li alloy Fatigue crack propagation Grain structure MICROCRACK 

分 类 号：TG132.3[一般工业技术—材料科学与工程]