Fast characterization framework for creep microstructure of a nickel-based SX superalloy with high-throughput experiments and deep learning methods

Nickel-based single crystal (SX) superalloys are the key materials of turbine blades in aircrafts, that the microstructure evolution during high temperature creep has critical effects on the thermo-mechanical properties. Research on microstructure evolution and establishing the quantitative relationship between microstructure evolution and creep conditions are of great significance for service safety assessment of nickel-based SX superalloys. High generation nickel-based SX superalloys generally have high cost on account of precision casting and the addition of Re and Ru which are rare and precious metals. Hence, it is necessary to develop a rapid characterization and analysis approach in terms of microstructure features of nickel-based SX superalloys. In this study, we integrated high-throughput experiment, large-scale high-resolution characterization and high-throughput quantitative analysis techniques to establish an efficient method for investigating the microstructure evolution of nickel-based SX superalloys during high temperature creep. The high temperature interrupted creep tests were carried out on the variable section specimens with arc surface to acquire the microstructures which are changed with creep stress continuously. High-resolution SEM with ALTLAS module was employed to quickly characterize the large-scale microstructure throughout the universal stress scale. Based on U-Net deep learning algorithm, an automatic dendrite identification model was established to segment the dendrite region quickly and accurately. And then, the γ/γ’ microstructure parameters of dendrite region were continuously quantitated using a logical algorithm. The quantitative correlation between microstructure evolution and creep conditions of nickel-based SX superalloys could be established, which shows tremendous potential and significance in the service safety assessment of nickel-based SX superalloys.