Tensile deformation accommodation in microscopic metallic glasses via subnanocluster reconstructions

Abstract

We present results on the structure and the atomistic mechanisms for tensile deformation accommodation of the Cu46Zr54 microscopic metallic glass. At equilibrium, 23% of the atoms belong to tiny Cu-centered icosahedral clusters (Cu-ICO) and approximately 41% Zr centered slightly larger ICO-like clusters. Under deformation, the number of Cu-ICOs remains dynamically constant until yielding through a continuous cluster destruction-recreation process. Plastic deformation occurs homogeneously and is locally accommodated through the formation of rhombic dodecahedral clusters with significant (∼2%) atomic density drop. These findings explain very recent experimental results demonstrating the fundamental differences of plastic deformation mechanisms between bulk metallic and microscopic glasses.