Revealing Nanoscale Solute-Rich Clusters in Bulk Metallic Glasses by Atom Probe Tomography

Bulk metallic glasses (BMGs) exhibit excellent mechanical properties due to their lack of long-range atomic ordering. However, understanding their structure-property relationships remains an unresolved challenge since traditional characterization methods have been unable to reveal the 3D nanostructures that control mechanical properties. In this study, a novel approach is developed that uses atom probe tomography (APT) cluster analysis to identify and visualize 3D nanoscale solute-rich clusters in Zr-based BMGs and quantify their size, composition, spatial distribution, and volume fraction. These results show that hardness variations in BMGs are driven by the volume fraction and distribution of solute-rich clusters. By inputting these experimentally determined parameters into a model for ductile phase softening, the deformation mechanisms of BMGs are elucidated as being controlled by the solute-rich clusters, and their possible relationship with topologically ordered short- and medium-range ordered clusters is discussed. This methodological breakthrough in characterizing structure-property relationships in metallic glasses is applicable to a wide range of multicomponent amorphous materials and is anticipated to enable major advances in glass science.