Al-Cu-Li合金轧制厚板的疲劳性能及断裂机理研究
Study on Fatigue Performance and Fracture Mechanism of Al-Cu-Li Alloy Rolled Thick Plate
投稿时间:2021-03-15  修订日期:2021-09-15
DOI:
中文关键词:  Al-Cu-Li合金厚板  疲劳性能  各向异性  析出相
英文关键词:Al-Cu-Li alloy thick plate  Fatigue properties  Anisotropy  Precipitation phases
基金项目:国家自然科学基金资助项目(51474101),National Natural Science Foundation of China(51474101)
作者单位邮编
李国爱 中国航发北京航空材料研究院 100095
王俭堂 烟台华新集团有限公司 
郝时嘉 中国航发北京航空材料研究院 
高文理 湖南大学材料科学与工程学院 
陆政 中国航发北京航空材料研究院 
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中文摘要:
      本文利用疲劳试验机、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等设备研究了95mm厚的Al-Cu-Li合金热轧板材不同方向的组织特征、疲劳性能和断裂机理。结果表明:Al-Cu-Li合金热轧厚板的力学性能和疲劳性能均存在各向异性,力学性能的规律为LT向(宽相)>L向(纵向)>ST向(高向),疲劳性能的规律为LT向>ST向>L向。Al-Cu-Li合金厚板的疲劳裂纹源主要出现在试样表面、近表面的夹杂物和晶界处,裂纹扩展过程中,LT向裂纹扩展路径较L向更曲折,ST向具有典型的解理特征。瞬断区形貌与静态拉伸断口相似,L向、LT向属于以塑性断裂为主,ST向以脆性断裂为主。晶界越多,裂纹扩展阻力越大,LT向和ST向的未溶第二相能够有效阻碍裂纹扩展,导致其疲劳性能优于L向。
英文摘要:
      In this paper, the microstructure characteristics, fatigue properties and fracture mechanism of 95mm Al-Cu-Li alloy thick plate in different orientations were studied by fatigue testing machine, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the mechanical properties and fatigue properties of Al-Cu-Li alloy thick plate were both anisotropic. The law of mechanical properties was LT direction (width direction) > L direction (length direction) > ST direction (height direction) and the law of fatigue properties was LT direction>ST direction>L direction. Fatigue crack sources of Al-Cu-Li alloy thick plate mainly appeared on the sample surface, near-surface inclusions and grain boundaries. During the crack propagation process, the crack propagation path in the LT direction was more tortuous than in the L direction, and the ST direction had a typical cleavage characteristic. The morphology of the instantaneous fracture zone was similar to that of the tensile fracture. The L-direction and LT-direction were mainly plastic fracture, and the ST-direction was mainly brittle fracture. The more grain boundaries, the greater the crack propagation resistance, and the undissolved second phase in the LT direction and ST direction can effectively hinder the crack propagation, resulting in better fatigue performance than the L direction.
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