Thermo-Span® is a precipitation hardenable superalloy that exhibits a low coefficient of thermal expansion over a broad temperature range, high tensile and rupture strengths, and good thermal fatigue resistance. This alloy offers a significant improvement in environmental resistance over CTX-1, CTX-3, and CTX-909 alloys due to the addition of chromium. It also possesses an excellent combination of tensile properties and stress rupture strength in the recrystallized condition with the use of common solution and age hardening treatments. Unlike the CTX-family of alloys, the use of specific braze-cycle age hardening treatments is not required for Thermo-Span® due to the higher solution treating temperature. Thermo-Span® should be considered for use in all applications for which the current low expansion superalloys are suited, in applications requiring resistance to thermal fatigue, and additional high temperature applications where moderate oxidation resistance is required for use.