Nanoindentation study on the room temperature creep characteristics of a senary Ti16.7Zr16.7Hf16.7Cu16.7Ni16.7Be16.7 high entropy bulk metallic glass

The room temperature creep behavior of a newly developed Ti16.7Zr16.7Hf16.7Cu16.7Ni16.7Be16.7 high entropy bulk metallic glass was investigated by nanoindentation measurements with various loading rates in comparison with that of a typical conventional Vitreloy 1 bulk metallic glass. A generalized Kelvin model was adopted to describe the creep curves. It was found that for both the two studied alloys, the creep displacement and strain rate sensitivity increases with increasing loading rate, indicating a positive loading rate effect. Vitreloy 1 BMG exhibits a more obvious loading rate effect compared with Ti16.7Zr16.7Hf16.7Cu16.7Ni16.7Be16.7 HE-BMG. The creep compliance and retardation spectra were also derived to study the creep mechanism. Compared with other developed high entropy alloys and bulk metallic glasses (e.g. Vitreloy 1 alloy), the studied HE-BMG possesses relatively small strain rate sensitivity values, indicating a good creep resistance. Based on the experimental results, the mechanisms of the unique creep resistance of Ti16.7Zr16.7Hf16.7Cu16.7Ni16.7Be16.7 high entropy bulk metallic glass have also been explained.