铝合金压印接头微动疲劳机理研究

压印连接是近年来新兴的连接方式，因其具有简单高效、低耗环保等优点，使得在应用连接方面越来越受到重视。疲劳破坏是机械构件失效的主要形式，疲劳过程中的微动磨损是造成零部件失效的主要原因之一。基于以上条件，对铝合金压印接头的疲劳性能进行了试验研究，结果显示疲劳失效部位主要集中在下板靠近压印点处，断口处发现大量微动磨屑，经能谱分析可以确定磨屑成分主要为氧化铝和金属铝；对疲劳失效断口和微动磨损区域进行了扫描电镜分析，发现压印接头的微动磨损部位主要分为两类，并对其进行了定义，一类定义为颈部微动磨损，另一类定义为环点板间微动磨损。分析发现颈部微动磨损所占比例随着外加载荷的大小而变化，且微动磨损是导致压印接头疲劳失效的重要因素。

Fretting Fatigue Mechanism Research of the Aluminum Alloy Clinched Joints

Mechanical clinching is a connection technology widely used in different industrial fields because of several advantages such as easy to operate, high efficiency, etc. Fatigue damage is a main failure mode of the metal mechanical part. Fretting wear is one of the reasons which lead to component failure. Tensile-shear tests and fatigue test were carried out to characterize the mechanical properties of the clinched joints of aluminum alloy sheet. Results show that the fatigue failure parts of the clinched joints are concentrated in the indentation of the lower sheet. There are many fatigue abrasive dust on the cracks. Energy spectrum analysis illustrated that chemical composition is aluminum oxide and metallic aluminum. Scanning electron microscopy analysis shows that there are two types of fretting wear modes which are defined. One was named neck fretting wear and the other is round-indentation fretting wear. The two types of fretting wear modes' proportion are changed by the applied load. Fretting wear is one of the important factors leading to fatigue failure of the clinched joint.