Dendritic coarsening model for rapid solidification of Ni-superalloy via electrospark deposition

Control of splat thickness in an electrospark deposition (ESD) process can be used to improve the mechanical properties of deposited Inconel 718. The lower cooling rates of thicker deposition splats obtained through higher energy ESD parameters result in greater subgrain coarsening and lower microhardness. A subgrain growth model and Hall-Petch relationship are used to quantify the extent of subgrain coarsening and the influence of splat thickness on hardness, with a 4.5 times reduction in splat thickness achieving a 20% increase in microhardness.