Microstructure evolution and mechanical properties of transient liquid phase bonded Ti-6Al-4V joint with copper interlayer

The microstructure evolution and mechanical properties of transient liquid phase bonded Ti-6Al-4V joint with copper interlayer was investigated by varying the bonding time at 930 degrees C. It was revealed that intensive metallurgical reactions occurred at the Ti-6Al-4V/Cu interface and integral joint consisting of TiCu, Ti2Cu layers and eutectoid structure was obtained for a bonding duration of 1 min. Prolonged holding time resulted in transformation of TiCu into Ti2Cu and subsequently progressive decomposition of the Ti2Cu phase. Ultimately, homogenized joint primarily composed of a -Ti matrix with tiny Ti2Cu platelets was obtained when bonding for 30 min. Tensile tests demonstrated that the homogenized joint exhibited mechanical properties comparable with that of the Ti-6Al-4V parent alloy. These experimental results demonstrate that the transient liquid phase bonding technique employing Cu interlayer is of great potential to be used for joining titanium based alloys. (C) 2015 Elsevier Ltd. All rights reserved.