Correlations between the ductility and medium-range order of bulk metallic glasses

A. Davani F, Hilke S, Rösner H , Geissler D, Gebert A, Wilde G

Abstract

Understanding ductility or brittleness of monolithic bulk metallic glasses requires detailed knowledge of the amorphous structure.The medium-range order (MRO) of ductile Pd40Ni40P20 and brittle Zr52.5Cu17.9Ni14.6Al10Ti5 (Vit105) was characterized prior to and afternotched three-point bending tests using variable-resolution fluctuation electron microscopy. Here, we show the presence of a second largerMRO correlation length in the ductile material, which is not present in the brittle material. The second larger correlation length accountsfor an increased heterogeneity, which seems to enable an easier shear band formation and thus explain the difference in deformability.