Bias factor of dislocation loops in quasicrystalline materials

TL;DR

This paper investigates how phasons in quasicrystals influence dislocation behavior and vacancy swelling, revealing that phasons reduce dislocation bias and potentially enhance resistance to irradiation-induced damage.

Contribution

It introduces a steady-state drift-diffusional model in toroidal geometry to analyze phason effects on dislocation bias in quasicrystals, a novel approach in this context.

Findings

Phasons significantly reduce dislocation bias towards interstitial absorption.

Quasicrystals may have increased resistance to vacancy swelling due to phason effects.

The model predicts altered defect dynamics in quasicrystalline materials.

Abstract

Vacancy swelling of quasicrystals under irradiation is considered. In quasicrystals, the evolution of dislocations is accompanied by the formation of phasons which are localized topological defects of the vacancy and interstitial types. At moderate temperatures the diffusivity of phasons is low which leads to the formation of ring-or disk-shaped phason trails inside dislocation loops. To find the capture efficiency of point defects by a dislocation loop with the complementary ring of phasons the steady-state drift-diffusional problem is solved in the toroidal geometry by the successive overrelaxation method. It is shown that phasons significantly reduce the bias of dislocations towards absorption of interstitial atoms. For this reason, quasicrystalline materials are predicted to exhibit increased resistance to vacancy swelling.