TY - CONF A1 - Lehmusto, Juho T1 - Initial oxidation of the refractory high-entropy superalloy AlMo0.5NbTa0.5TiZr N2 - In contrast to traditional alloys, which are typically based on a single dominant element, high-entropy alloys (HEAs) consist of five or more principal elements in roughly equal proportions. These complex alloys often exhibit superior characteristics compared to conventional alloys, including enhanced strength and hardness, exceptional wear resistance, high structural stability, and strong resistance to oxidation. Despite these promising characteristics, the vast compositional space of HEAs means that only a limited number have been thoroughly investigated for their mechanical and chemical behavior. One notable example is the refractory high-entropy superalloy AlMo0.5NbTa0.5TiZr, which represents a newly emerging class of materials. This alloy features a nanoscale microstructure composed of B2 and bcc phases, resulting in compressive strength at elevated temperatures that surpasses that of conventional Ni-based superalloys. Such performance offers potential benefits for improving turbine efficiency in aerospace and energy generation applications. However, the alloy’s microstructure is known to be sensitive to annealing. Specifically, its mechanical properties deteriorate when intragranular hexagonal Al-Zr-based intermetallic compounds form, likely due to issues with phase stability. On the other hand, the inclusion of Al has been shown to enhance oxidation resistance. Nevertheless, HEAs are also known to develop pronounced internal aging zones caused by diffusion during oxidation processes. These findings indicate a need for further investigation into the thermodynamic stability of this alloy. In addition, its oxidation behavior—both at the surface and within the material—remains incompletely understood. This ongoing research explores the oxidation behavior of the AlMo0.5NbTa0.5TiZr alloy at temperatures ranging from 800 °C to 1000 °C. The influence of water vapor on the oxidation process is also examined. Ultimately, the goal is to integrate insights into the alloy’s structural, mechanical, and chemical characteristics at high temperatures. T2 - Gordon Research Conference - High Temperature Corrosion CY - New London, United States DA - 16.07.2023 KW - High-Entropy superalloy KW - Phase stability KW - Microstructural evolution KW - Oxidation behavior KW - High-Temperature Performance PY - 2023 AN - OPUS4-63851 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -