| Abstract Scope |
This paper presents the development of AMS20, a novel third-generation single crystal superalloy designed for the next generation of aeroengines. The alloy design utilizes a computational approach that combines empirical models and CALPHAD calculations to identify compositions meeting targeted specifications. This methodology facilitates the selection of the final AMS20 alloy composition, aiming to optimize high temperature creep properties while preserving excellent high temperature oxidation resistance. The alloy was cast and single crystal bars were grown using the conventional Bridgman method. Subsequently, appropriate solution and aging treatments were developed, and the tensile and creep properties of AMS20 were evaluated. A comparative analysis was performed against reference second and third-generation single crystal superalloys, namely CMSX-4, CMSX-10K, CMSX-4 Plus, and AGAT. Results indicate that AMS20 exhibits a remarkable combination of high temperature creep and oxidation resistance. Specifically, AMS20 demonstrates a creep life at 1200 °C comparable to CMSX-10K alloy, while its cyclic oxidation performance at 1150 °C is akin to second-generation CMSX-4 alloy and notably superior to third-generation reference alloys. However, it is important to note that initial aging results highlight the sensitivity of AMS20 alloy to TCP phases at 1050 °C and its relatively narrow high temperature processing windows. Yet AMS20 remains a promising single crystal superalloy for the future generation of aircraft engines. |