Shear induced crystallization of an amorphous system

TL;DR

This study uses molecular dynamics simulations to explore how stationary shear flow affects crystallization in a glassy system, revealing dual effects on topological ordering and detailing the stages of shear-induced crystallization.

Contribution

It provides new insights into the dual role of shear flow in promoting and suppressing crystallite formation and characterizes the stages of shear-induced ordering in amorphous materials.

Findings

Shear promotes crystallite formation but suppresses large clusters.

Crystallization occurs in two stages: growth and alignment.

Two phenomenological relations between shear rate and ordering time are identified.

Abstract

The influence of a stationary shear flow on the crystallization in a glassy system is studied by means of molecular dynamics simulations and subsequent cluster analysis. The results reveal two opposite effects of the shear flow on the processes of topological ordering in the system. Shear promotes the formation of separated crystallites and suppresses the appearance of the large clusters. The shear-induced ordering proceeds in two stages, where the first stage is related mainly with the growth of crystallites, whereas the second stage is due to an adjustment of the created clusters and a progressive alignment of their lattice directions. The influence of strain and shear rate on the crystallization is also investigated. In particular, we find two plausible phenomenological relations between the shear rate and the characteristic time scale needed for ordering of the amorphous system under shear.