Amorphization activated by semicoherent interfaces of FCC/BCC HEA multilayers during deformation

Eutectic high entropy alloys (EHEAs) are widely advocated materials for overcoming the strength -ductility trade-off due to their abundant heterogeneous interfaces. However, the lack of a full under-standing of the plastic carrier-interface interaction mechanism obscures the essential role of the interface in the simultaneous enhancement of strength and ductility. To elucidate the underlying mechanisms from an interface perspective, FCC/BCC multilayers with semicoherent and coherent interfaces were pre-pared by a magnetron sputtering system. The mechanical properties and microstructure evolution of multilayers were investigated by using nanoindentation, X-ray diffractometer and transmission electron microscopy, respectively. Moreover, the dislocation motion behavior and stress distribution during plas-tic deformation were analyzed by MD simulation. It is found that the plastic deformation behavior and mechanical properties of EHEAs are sensitive to the heterogeneous interfacial structure. During plastic deformation, the coherent interface facilitates the continuous slip of dislocations, whereas the semico-herent interface promotes amorphization by dislocations pileup. The results are important for under-standing the plastic carrier-interface interaction mechanism, and the findings provide new insights for the development of high strength-ductility HEA materials. (c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

In this study, multilayer structures with different interface structures were prepared to investigate the mechanical properties and microstructure evolution of EHEAs during plastic deformation. Molecular dynamics simulations were used to analyze dislocation motion and stress distribution. The results showed that the plastic deformation behavior and mechanical properties of EHEAs are sensitive to the heterogeneous interface structure, with the coherent interface facilitating dislocation continuous slip and the semicoherent interface promoting dislocation pileup-induced amorphization. These findings are important for understanding the plastic carrier-interface interaction mechanism and provide new insights for the development of high strength-ductility HEA materials.