Impact of surface micro-dimples on machinability of Inconel 718 alloy

Abstract

Used extensively in the aerospace industry, the superalloy Inconel 718 is deemed hard to cut because of its rapid work hardening, low thermal conductivity, and excessive shear strength. Proposed here is patterning Inconel 718 with micro-dimples using electrochemical machining and electrical discharge machining prior to conventional cutting. How this micro-dimple patterning influences the machinability of Inconel 718 is analyzed via orthogonal cutting experiments, and with the optimal parameters, the cutting temperature is lowered by 45.5% and the cutting forces are reduced significantly, i.e., the tangential cutting force and the thrust force are reduced by 61.1% and 47.1%, respectively. The predictions of finite-element simulations agree with experimental observations, and it is concluded that dimpled Inconel 718 offers significantly improved tool wear and surface integrity.