부산대학교 도서관

High Entropy Alloys (HEAs), as a new class of alloy materials, have shown broad application prospects in the field of impact engineering due to their outstanding performance characteristics. However, existing research on their mechanical behavior has primarily focused on quasi-static conditions, with relatively limited studies on HEAs produced by additive manufacturing. This paper systematically investigates the dynamic deformation behavior and microstructural evolution of additive manufactured FeCoNiCrMn high entropy alloys under constant high strain rates. A series of detailed dynamic tensile tests were conducted on the alloy at various constant high strain rates using a high-speed tensile testing machine. The grain morphology was examined using Electron Backscatter Diffraction (EBSD) technology, and the hardening mechanisms related to strain rate were revealed through precise calculation of dislocation density. The study found that the additive manufactured FeCoNiCrMn high entropy alloys exhibited significant strain rate sensitivity under high strain, especially showing considerable mechanical performance improvement at extremely high strain rates, indicating that the alloy has excellent application potential under rapid loading conditions. Furthermore, the analysis of the alloy's fracture surfaces revealed a mix of ductile and brittle fracture features, further confirming the complex stress response mechanism of the material under dynamic loading. These findings not only reveal the behavioral characteristics of additive manufactured FeCoNiCrMn high entropy alloys under dynamic loading conditions but also provide valuable guidance for their application in areas such as high-speed impact and machining.