Comparative study of finishing techniques for age-hardened Inconel 718 alloy

Abstract

Inconel 718 is a widely used alloy in the aeronautic sector due to its excellent mechanicaland corrosion wear resistance under high temperature conditions. However, its goodmechanical properties can be a double edge sword in terms of manufacturing, especially inthose processes based in mechanical principles, such as machining or forming. Consid-ering that most aeronautic components are exposed to cyclic load and temperature, fatigueresistance becomes critical, and therefore, the finishing processes. The surface integrity ofa component plays an important role on its fatigue behaviour, as the most common crackinitiation area is usually the surface. The present work compares three differentmechanical finishing processes that confer better surface properties to the component:polishing, burnishing, and hammer-peening. Each one achieves different degrees ofroughness, and residual stress on the surface. The study is not only focused on theresultant mechanical properties, but also in productivity and process robustness. It isconcluded that each technology excels in a different property.