Dislocation slip induced tensile plasticity and improved work-hardening capability of high-entropy metallic glass composite

Abstract The high-entropy metallic glasses (HEMGs), combining the characteristics of high-entropy alloys (HEAs) and metallic glasses (MGs), have recently appeared and become the research focus, due to their good glass-forming ability and high strength. However, the application of HEMGs as structural material is restricted owing to the limited tensile plasticity and absence of dislocation-dominated deformation mechanism. To resolve this pressing issue, a stable β-phase HEMG composite (β-type HEMGC) Ti20Zr20Hf20Nb16Co5Be19 composed of the bcc refractory HEA (RHEA) dendrites and the HEMG matrix was fabricated. Ti20Zr20Hf20Nb16Co5Be19 not only exhibits good tensile ductility, but also has the improved work-hardening capability under room temperature tension. Essentially, the dislocation-dominated deformation mechanism plays a significant role in achieving the excellent combination of good tensile plasticity and improved work-hardening capability of the stable β-type HEMGC. The tensile ductility of Ti20Zr20Hf20Nb16Co5Be19 is attributed to the dislocation-slip mechanism induced by high-stable HEA dendrites, and the dislocation pile-up phenomenon has a great influence on the improved work-hardening capability of composite. The present results provide an indepth understanding of the deformation behavior of stable β-type HEMGCs, and a reference for how to improve the strength-ductility combination of HEMG-matrix composites.