Superalloys, sustainability and applications

Abstract

Superalloys are resistant to extreme mechanical stress at temperatures above 70% of their melting point. Superalloys have exceptional properties such as resistance to creep and thermal fatigue, mechanical strength at high temperatures, resistance to corrosion and oxidation, and resistance to phase separation with time. Superalloys are primarily based on nickel (Ni), but cobalt (Co)-based and iron (Fe)-nickel-based variants are also available. Superalloys are categorized based on their primary element: First, nickel-based superalloys are mostly used in superalloy applications. Second group is cobalt-based superalloys. For example, Haynes 188 and Stellite 6B are some of such superalloys. They can be used in various fields including gas turbine blades, dental implants, and industrial furnace parts applications. Third group is nickel-iron-based superalloys. They can be used in different application areas such as turbine disks and boiler components. In the presented article, exceptional properties of superalloys are identified and classified depending on the processing route and primary element. Then, the sustainability of superalloys is criticized for the sake of environmental perspective. The challenges and future perspectives of alternative alloy development and superalloys are also investigated to provide potential researchers with insights into the benefits and disadvantages of the virgin field of superalloys.