On the notch sensitivity of CuZr nanoglass

摘要

Recently, nanoglass (NG) was found to exhibit a surprising homogeneous superplastic deformation behavior. However, how the presence of notch affects its mechanical properties remains unexplored. Here, we perform molecular dynamics simulations on a superplastic Cu50Zr50 NG containing a pre-existing notch under tensile loading, with focus on the notch sensitivity. Our results show that when the notch size is smaller than or comparable to the average grain size (d), the NG still exhibits a superplastic deformation and shows notch-insensitivity. When the notch size is larger than d, however, the NG fails by localized shear banding emanating from the notch root and shows notch-sensitivity. The origin of this transition arises from the competition between the shear band nucleation induced by the stress concentration at the notch root and the growth of shear transformation zones distributed in the glass-glass interfaces. Our results provide useful guidelines for the design and engineering of NG with notch for structural applications.