A study on the effect of bonding time on the properties of Al7075 to Ti-6Al-4V diffusion bonded joint

Joining of two dissimilar aerospace alloys Al7075 and Ti-6Al-4V was carried out using transient liquid phase bonding and 50 mu m thick Sn-10Zn-3.5Bi film as interlayer. Cu coating was electrodeposited onto the joining surfaces and bonds were made at 500 degrees C for various bonding times. At low bonding times, eutectic phases between Al and Cu were formed inside the interlayer and along the Al7075 grain boundaries. Also, intermetallics such as TiAl and Ti3Al were formed at bonding time of 60 min. The results showed that as bonding time increases up to 60 min, the hardness of the joint interface increases which can be attributed to the intermetallic compounds formation. Moreover, the width of the joint region decreases as bonding time increases. The strength of the bonds increases with increasing bonding time and reaches to 30 MPa at 60 min. (C) 2012 Elsevier B.V. All rights reserved.