Interfacial microstructure characteristics and mechanical properties of X65/IN625 composite plates with different interlayers

The brittle Laves phase forming on the interfaces of nickel-based composite plate has evident effect on its application. For the purpose of decreasing the formation of brittle phase and improving mechanical performance, X65/IN625 composite plates were synthesized using vacuum hot pressing under varying conditions. The investigation was focused on understanding the bonding properties and interfacial microstructure of these composites. The results show that the optimal process is 30 min holding time, 30 MPa pressure and 1050 °C heating temperature. It is worth noting that after the addition of nickel and invar alloy interlayers to the composite plate, the interface bonding strength of the composite plate is significantly improved by approximately 35 % (341 MPa) and 17 % (305 MPa), respectively, compared to plates without interlayer. This is because the addition of nickel and invar alloy layer can decrease the width of the diffusion zone near the interface and effectively inhibit the diffusion of Fe element, thereby reducing the formation tendency of Laves phase, and promoting the formation of Ni2(Cr,Mo).