Influence of Process Parameters on the Microstructural and Mechanical Characteristics of TLP Bonded IN718

Abstract

study explores the role of process parameters in joining IN718 with the TLP bonding process is explored. Microstructure evolution and mechanical performance of the bond are investigated using scanning electron microscopy, tensile test, and micro-hardness test. The bond metallurgy showed three distinct zones: the base material zone, the diffusion-affected zone containing a large number of boride precipitates, and the isothermal solidification zone. Further investigation reveals that the ISZ contains a few brittle intermetallic particles, which reduce the mechanical properties of the bond. The results demonstrates that higher bonding temperature, time, optimal interlayer thickness, and pressure enhance the mechanical and microstructural properties of the bond. The bond formed at 1423 K bonding temperature, 1.5 h holding time, 80 μm interlayer thickness, and 12.5 kg load demonstrates the highest strength of 625 MPa.