Deformation mechanisms in a precipitation-strengthened ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures

摘要: Abstract The ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this at high temperatures needs to be further improved, which requires fundamental understanding high-temperature deformation mechanisms scales individual phases and grains. In situ neutron diffraction has been utilized investigate lattice strain evolution microscopic load-sharing during tensile elevated temperatures. Finite-element simulations based on crystal plasticity theory are employed compared with experimental results, both qualitatively quantitatively. Based these interphase intergranular load-partitioning studies, it found that change from dislocation slip those related climb, diffusional flow possibly grain boundary sliding, below 873 K, respectively. Insights into microstructural design enhancing also discussed.