钛合金压印接头疲劳性能与微观分析

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,在连接应用方面越来越受到重视,而疲劳破坏是机械零件失效的主要形式。对钛合金压印接头的疲劳性能进行了实验研究,与母材的力学性能进行了对比分析,并对疲劳失效断口进行了断口分析和能谱分析。实验结果显示钛合金压印接头的平均拉伸-剪切强度约为同等尺寸材料拉伸-剪切强度的36.7%;钛合金压印接头的疲劳极限约为材料疲劳极限的46%,平均载荷约为接头最大静强度的42%。微观特征显示断口呈脆性疲劳断裂特征,由于微动磨损和氧化作用产生了成分为氧化钛的微动磨屑,且其硬度较高,因此在微动过程中起到磨粒的作用,从而加速了磨损和裂纹扩展,最终导致疲劳失效。

Fatigue Property and Microanalysis of Clinched Joints of Titanium Alloy

Mechanical clinching is a widely used connection technology in different industrial fields. Because it has several advantages such as simple operating process, high efficiency and so forth. Fatigue damage is a main failure mode of the metal mechanical part. In this paper, tensile-shear tests and fatigue test were carried out to characterize the mechanical properties of the clinched joints of titanium alloy. The tensile-shear strength of the clinched joint of titanium alloy was about 36.7% of that of the material itself with equal size. The fatigue strength for titanium alloy sheets joined by clinching was about 46% of that of titanium alloy and about the average load was about 42% of the static strength of clinched joints. Microscopic characteristics showed that the fracture was brittle fatigue fracture. Fatigue abrasive dust with high hardness was produced due to the fretting wear and oxidation which acted as micro abrasive in the process of fretting wear. In this way, it accelerated the abrasion and crack propagation and eventually leaded to fatigue failure.