Effect of microstructure on tensile properties of electrospark deposition repaired Ni-superalloy

Cavities introduced to Inconel 718 tensile specimens were repaired with the use of electrospark deposition (ESD) and tensile properties of repaired specimens were investigated. Reduced energy input during ESD resulted in a larger number of splat boundaries and greater yield strength recovery during tensile testing. Analysis of the fracture surface showed a trans-splat and inter-splat crack propagation pathway, with splat boundaries exhibiting lower fracture toughness than material within the splats. Changes in crack propagation direction were attributed to grain growth across splat boundaries and brittle secondary phases forming within splats during ESD.