Electric-assisted diffusion bonding of Al_0.3CoCrFeNi high-entropy alloys: mechanisms and properties

The excellent irradiation resistance, high strength and plasticity exhibited by high-entropy alloys (HEAs) make it candidate for engineering applications. Diffusion bonding of Al_0.3CoCrFeNi single-phase HEAs was carried out using electric-assisted diffusion bonding (EADB), and the effect of bonding temperature on the evolution of the interfacial microstructure and the mechanical properties was investigated. The results indicate that as the bonding temperature increases, the pores at the interface gradually decrease in size and undergo closure. The electric current significantly promotes the pore closure mechanism dominated by plastic deformation at the diffusion interface and promotes the recrystallisation behavior at the interface, and the fracture mode changes from intergranular fracture at the interface to jagged fracture along the grains spanning the weld parent material. Due to the activation effect of EADB, higher-strength diffusion bonding of high-entropy alloys can be achieved at the same temperature compared with the conventional hot-pressure diffusion bonding (HPDB) process.