A critical review on the machinability aspects of nickel and cobalt based superalloys in turning operation used for aerospace applications

Cobalt- and nickel-based superalloys are being extensively used in aerospace, automotive and medical applications due to their specific properties, which include working at high temperatures and stresses, good corrosion and oxidation resistance. This paper incorporates a review on the machinability aspects of nickel- and cobalt-based superalloys in turning operations. The machinability aspects like tool wear and surface integrity are critically reviewed for turning operation. Also, the effect of parameters, such as coating, cooling methods, cutting speeds and feed rate on tool wear, is reviewed critically. The different tool wear mechanisms that occur during machining of these superalloys are studied along with surface integrity, which include surface roughness and microstructures. Lastly, conclusions drawn are based on parameters that need to be improved for sustainable machining of nickel- and cobalt-based superalloys. This review will guide researchers and manufacturers for proper understanding of parameters selection.