Modulation of plasticity by crystalline precipitates in CuZr metallic glasses

Abstract

Amorphous/crystalline composites consist of crystalline phases embedded in an amorphous matrix that offer the possibility for synthesizing materials with tailored properties. Here, molecular dynamics simulations were performed to study the plastic behavior of CuZr metallic glasses (MGs) with CuZr B2 spherical precipitates under tensile tests. Shear transformation zones were observed to nucleate at the MG/B2 interface, a phenomenon that was more remarkable at larger precipitate sizes. Furthermore, large precipitates acted as barriers for shear band (SB) propagation. To overcome such barriers, and owing to the lack of phase transformation and plastic activity in the CuZr B2 structures, SBs displaced the precipitates, leading to increased stress in the sample. In addition, the degree of strain localization was higher when the precipitates were closer to each other. Thus, the plasticity in our MG composites was modulated by the size and distribution of the precipitates.