Deformation Behavior and Mechanisms of fcc High-Entropy Alloys: Insights from Neutron Diffraction

Abstract:

The multi-principal element characteristic of high-entropy alloys has revolutionized the conventional alloy design concept of single-principal element, endowing them with excellent mechanical properties. However, owing to this multi-principal element nature, high-entropy alloys exhibit complex deformation behavior dominated by alternating and coupled deformation mechanisms. Therefore, elucidating these intricate deformation mechanisms remains a key challenge in current research. Neutron diffraction (ND) techniques offer distinct advantages over traditional microscopic methods for characterizing such complex deformation behavior. The strong penetration capability of neutrons enables in-situ, real-time, and non-destructive detection of structural evolution in most centimeter-level bulk samples under complex environments, and ND allows precise characterization of lattice site occupations for light elements, such as C and O, and neighboring elements. This review discussed the principles of ND, experiment procedures, and data analysis. Combining with recent advances in the research about face-centered cubic high-entropy alloy, typical examples of using ND to investigate the deformation behavior were summarized, ultimately revealing deformation mechanisms dominated by dislocations, stacking faults, twinning, and phase transformations.