Laves phase crystal analysis (LaCA): Atomistic identification of lattice defects in C14 and C15 topologically close-packed phases

TL;DR

LaCA is a novel atomistic analysis method that identifies crystal structures and defects in Laves phases, including C14 and C15, and detects deformation mechanisms, advancing defect analysis in complex TCP phases.

Contribution

The paper introduces LaCA, a new method combining existing algorithms to identify structures and defects in Laves phases, including polytypes and deformation mechanisms.

Findings

Successfully identifies C14 and C15 Laves phases and their defects.

Detects deformation mechanisms like synchroshear and non-basal dislocations.

Extensible to other topologically close-packed phases.

Abstract

The identification of defects in crystal structures is crucial for the analysis of atomistic simulations. Many methods to characterize defects that are based on the classification of local atomic arrangement are available for simple crystalline structures. However, there is currently no method to identify both, the crystal structures and internal defects of topologically close-packed (TCP) phases such as Laves phases. We propose a new method, Laves phase Crystal Analysis (LaCA), to characterize the atomic arrangement in Laves crystals by interweaving existing structural analysis algorithms. The new method can identify the polytypes C14 and C15 of Laves phases, typical crystallographic defects in these phases, and common deformation mechanisms such as synchroshear and non-basal dislocations. Defects in the C36 Laves phase are detectable through deviations from the periodic arrangement of the C14 and C15 structures that make up this phase. LaCA is robust and extendable to other TCP phases.