Can nickel alloys be used at high temperatures?

One of the main advantages of nickel-based alloys is their ability to operate at elevated temperatures compared with stainless steels and other alloys. Their original development was driven by the need for suitable alloys for the very first jet engines, although grades have subsequently been developed for a wider range of industrial applications.

Generally speaking, there will be a reduction in mechanical properties as the operating temperature increases. For instance, Alloy 718 (Inconel 718, UNS N07718, 2.4668) retains most of its room temperature strength up to c. 650degC, and it resists oxidation up to a similar temperature. However, Alloy 625 (Inconel 625, UNS N06625, 2.4856) resists oxidation up to c. 1000degC, although suffers a similar drop in strength at c. 650degC.