刘莹莹,李洁洁,李嘉懿,任凯鑫,薛希豪

• 1:西安建筑科技大学冶金工程学院

摘要(Abstract)：

采用芯棒直接挤压的方法对不同尺寸的7050-T7451铝合金斜耳片进行孔挤压强化,并采用光学显微镜、扫描电镜、透射电镜和疲劳试验等研究孔挤压前后耳片的组织和疲劳性能。结果表明:经孔挤压强化后7050-T7451铝合金斜耳片的显微组织产生了大量的高密度位错,并缠结成位错胞状结构,其疲劳性能也得到了显著地提高,尤其对小尺寸耳片的提高效果更为明显,提高了83.86%,而大尺寸耳片在特定的峰值应力下其疲劳寿命可提高68.92%。这是因为耳孔内壁表层的金属受到芯棒挤压产生了剧烈的塑性变形,形成了组织强化层和残余压应力层,使得疲劳裂纹源的位置和数量发生了改变且疲劳辉纹宽度变窄,这些均降低了孔壁边缘的应力集中系数,减缓了裂纹的萌生和扩展速率,从而提高了耳片的疲劳性能。

关键词(KeyWords)： 7050-T7451合金耳片;孔挤压强化;显微组织;疲劳性能;断口形貌

Abstract:

Keywords:

基金项目(Foundation): 陕西省重点研发计划国际合作项目(2020KW-033);; 陕西省教育厅产业化项目(20JC024);; 西安建筑科技大学第十五批本科生科研训练计划(SSRT)项目

作者(Author): 刘莹莹,李洁洁,李嘉懿,任凯鑫,薛希豪

DOI: 10.13289/j.issn.1009-6264.2020-0458

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