摘要
对7075-T6铝合金激光复合焊焊接接头的疲劳寿命进行了探究。结果表明:疲劳裂纹萌生寿命与疲劳寿命之间存在着一定的比例关系。对于母材试样,该比值为64.5%;而对于焊接接头试样,该比值为20.2%。疲劳断口表面观察发现,母材试样的疲劳断口上存在大量韧窝,而焊接接头试样疲劳断口上存在许多气孔。这些气孔被认为是引起焊接接头疲劳裂纹萌生寿命急剧下降的主要原因。
The fatigue lifetime of the laser-MIG hybrid welded joint of 7075-T6 aluminum alloy was studied by in-situ observation. The results show that there exists a strong relationship between the fatigue crack initiation lifetime and fatigue failure lifetime. For the base metal specimens the ratio of fatigue crack initiation lifetime and fatigue failure lifetime is about 64.5%,while for the welded joint specimens it is about 20.2%. The observation of fatigue fracture surface indicates that there are a large number of dimples in the base metal specimens,while lots of gas porosities appear in the welded joint specimens instead. These gas porosities are regarded to be the reason of lower fatigue crack initiation lifetime.
作者
张寅
宋西平
常丽艳
吴圣川
Zhang Yin Song Xiping Chang Liyan Wu Shengchuan(State Key Laboratory for Advanced Metals and Materiala, University of Science and Technology Beijing, Beijing 100083, China State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第9期2411-2416,共6页
Rare Metal Materials and Engineering
基金
National Natural Science Foundation of China(21171018,51271021)
关键词
铝合金
焊接接头
原位观察
疲劳寿命
aluminum alloy
welded joint
in-situ observation
fatigue lifetime
