Microstructural evolution and properties of TLP diffusion bonding super-Ni/NiCr laminated composite to Ti-6Al-4V alloy with Cu interlayer

Transient liquid phase (TLP) diffusion bonding super-Ni/NiCr laminated composite to Ti-6Al-4V alloy was performed at 950 degrees C with the pressure of 5 MPa. Two configurations (super-Ni/Cu/Ti-6Al-4V and Ni80Cr20/Cu/Ti6Al-4V) were designed to explore interfacial microstructure evolution and mechanical properties. Results showed that the joint of laminated composite and Ti-6Al-4V alloy was mainly divided into two diffusion layers and a reaction layer. The interfacewas composed of Ni(Cu), Cu(Ni), Ti2Cu, TiCu, Ti3Cu4, Ti2Cu3 and Ti-Cu eutectic microstructure. The width of each layer increased with prolonging the bonding time and the growth rate of interfacial layers was dominated by the diffusion rate of alloying elements i.e. Cu, Ni and Ti. The maximum value of shear strength for both two configurations was about 58 MPa. (C) 2017 Published by Elsevier Ltd.