Advanced Techniques in Machining of Aerospace Superalloys: A Review

Abstract

Aerospace Superalloys are heat-resisting alloys based on nickel, nickel-iron, or cobalt that exhibit a combination of mechanical
strength and resistance to surface degradation. They have unique combination of properties like high strength at elevated
temperatures, resistance to chemical degradation and wear resistance & ability to maintain these properties at elevated
temperatures severely hinders the machinability of these alloys, thus they are generally referred to as difficult-to-cut alloys. The
aerospace and space sector has traditionally been promoter for the development and application of advanced superalloys. The
demand for these materials is generally spurred by the performance requirement of component, which usually an integral part of
complex technical system. Improvements achieved from research and development activities in this area have particularly
enhanced the machining of difficult to cut nickel base and titanium superalloys that have exhibited low machinability due to their
peculiar characteristics such as poor thermal conductivity, high strength at elevated temperature, resistance to wear and
chemical degradation, etc. The present review paper highlights an overview of major advances in machining techniques that have
resulted to step increase in machinability. Hence lower manufacturing cost, without adverse effect on the surface finish, surface
intergrity, circularity and hardness variation of machined component.