TA1纯钛点焊接头的疲劳性能分析

针对1.5 mm厚的TA1纯钛板电阻点焊接头,开展疲劳实验研究。利用超声波扫描显微镜对纯钛板点焊接头进行扫描,获得接头的C扫描图像;对接头进行拉剪实验,获得接头失效载荷;研究纯钛板点焊接头的疲劳性能,建立载荷-寿命曲线,对疲劳断口进行电镜扫描,分析疲劳裂纹扩展形式。结果表明,随着焊接电流增大,超声C扫描图像所测得的焊核直径均值随之增大,且C扫描图像可表征飞溅等焊接缺陷。载荷水平为10%、13%、30%对应的疲劳寿命平均值分别为1 753 302、261 193、8 263次。接头主要的疲劳失效模式为母材"眉状"断裂失效,裂纹源位于两板内侧焊核与母材交界的热影响区,在疲劳裂纹的稳定扩展区存在明显的塑性疲劳条带。

Fatigue Property Analysis of TA1 Pure Titanium Spot Welding Joint

Carried out the research of fatigue for the 1.5 mm thick TA1 titanium welded joints. Ultrasonic scanning microscope was used to scan the spot welded joint of pure titanium plate, and the C scanning image of the joint was obtained; The tensile strength of the welded joint was tested and the tensile strength of the joint was obtained. The fatigue property of the spot welding joint was studied. The load-life curve was fitted, The fatigue fracture was scanned by electron microscope and the form of fatigue crack propagation was discussed. The results show that with the increase of the welding current, the value of the nugget diameter measure by ultrasonic C scanning image increases, and the C scanning image can be used to characterize the welding defects such as spatter. When the lord level is 10%, 13%, 30%. The average fatigue life is about 1753302, 261193, 8263 times. The joints main fatigue failure for the parent material "eyebrow" fracture failure mode, crack source is located in the heat affected zone at the junction of nugget and base metal, There are obvious plastic fatigue striations in the stable extension region of fatigue crack.