Active joining of Ti-6Al-4V with electroplated Cu thin film

摘要

Joining of Ti-6Al-4V with thin film copper fillers was developed using an active infrared processing technique. The process includes rapid infrared heating of the specimen to 1125℃, and holding at that temperature for 60 s in flowing argon without vacuum, then followed by rapid cooling. The copper thin film filler was electroplated to various thicknesses: 1,2,4 and 8 μm. Excellent wetting between copper and Ti-6 Al-4V was observed in all joints. High joint shear strengths were obtained for all joints. The highest joint strength, 616 +- 10 MPa, was obtained with 2 μm filler thickness. This joint strength is significantly higher than the shear strength of pure copper, 174 MPa, or Ti-6Al-4V, 542 MPa. When the filler material was only 1 μm, the joint zone was not completely filled. X-ray diffraction analysis on the as fractured joint surface revealed the presence of intermetallic compounds when joined with 4 and 8 μm copper fillers but it disappeared when joined with 1 and 2 μm copper fillers.