Investigation of Mechanical and Microstructural Characteristics of Diffusion-Bonded CpAl/IN718 Interface

Diffusion bonded joint of Commercially Pure Aluminum (CpAl) with Inconel 718 (IN718) superalloy was investigated for its mechanical and microstructural characteristics. Diffusion Bonding (DB) of CpAl/IN718 was performed at 500 °C for 60 minutes using vacuum tube furnace in the presence Argon (Ar) gas under pressure at a heating rate of 10 °C/minutes followed by furnace cooled. The resultant joint interface was investigated by using Optical and Scanning Electron Microscopy (OM and SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), microhardness and shear strength. The microstructural analysis shows the formation of various Intermetallic Compounds (IMCs) at the bonding interface, such as NiAl 3, FeAl 2 , FeAl 3 , Fe 2 Al 5 along with austenitic matrix, which was confirmed by XRD. Additionally, the hardness of the bonding interface was 15% and 255 higher as compared to BM of IN718 and CpAl respectively. Lastly, an average lap shear strength of 61 MPa was achieved with a joint efficiency of 84%.