孔挤压强化对2024铝合金疲劳性能的影响  

Influence of hole cold expansion on fatigue resistance of 2024 aluminum alloy

作　　者：王连庆[1] 卞江 张晗[3] 吴圣川[3] WANG Lianqing;BIAN Jiang;ZHANG Han;WU Shengchuan(State Key Laboratory for Advanced Metals&Materials,University of Science&Technology Beijing,Beijing 100083,China;School of Mathematics&Physics,University of Science&Technology Beijing,Beijing 100083,China;State Key Laboratory of Traction Power,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]北京科技大学新金属材料国家重点实验室,北京100083 [2]北京科技大学数理学院,北京100083 [3]西南交通大学牵引动力国家重点实验室,成都610031

出　　处：《航空材料学报》2020年第6期45-51,共7页Journal of Aeronautical Materials

基　　金：国家自然科学基金大科学装置联合培育项目(U2032121)。

摘　　要：孔边应力集中易导致飞机结构疲劳失效,从而引发灾难性事故。为研究孔挤压强化对2024-T351铝合金板材疲劳寿命及性能改善的影响,在疲劳试验机上进行孔挤压前后铝合金板材试件的疲劳性能测试,采用X射线衍射测量及有限元仿真表征孔边残余应力分布。通过扫描电镜和透射电镜观察疲劳断口、疲劳条带及微区组织变化,揭示孔边微结构变化与疲劳寿命的关系。结果表明:孔挤压显著提高了2024-T351铝合金板材的疲劳性能,过盈量0.4 mm时增寿效果较好,疲劳极限增幅约为42%。The effect of stress concentration around the hole easily leads to fatigue failure of aircraft structures,and usually causes catastrophic accidents.In order to elucidate the influence of cold expansion on the fatigue life of AA2024-T351 specimens,fatigue tests of specimens before and after cold expansion were accomplished on high frequency fatigue test machine.Combining the finite element simulation with X-ray diffraction measurement,the evolution of residual stress around the hole was thus investigated.Meanwhile,scanning electron microscope(SEM)and transmission electron microscope(TEM)were employed to observe the fatigue fracture morphology,fatigue striation and microstructure characteristics,and to explore the influence of microstructure features on fatigue life.Research results show that the cold expansion with 0.4 mm can significantly improve the fatigue resistance of AA2024-T351 specimens,and the fatigue limit can be increased by about 42%.

关 键 词：孔挤压 疲劳寿命 2024-T351铝合金 有限元仿真 残余应力 

分 类 号：TG379[金属学及工艺—金属压力加工]