Influence of chemical disorder on energy dissipation and defect evolution in concentrated solid solution alloys.

Yanwen Zhang,Magdalena Caro,Hongbin Bei,Chenyang Lu,William J Weber,Lumin Wang,G Malcolm Stocks,Ke Jin,Brian C Sales,Laurent K Béland,German D Samolyuk,Roger E Stoller,Alfredo Caro

doi:10.1038/ncomms9736

Abstract

A grand challenge in materials research is to understand complex electronic correlation and non-equilibrium atomic interactions, and how such intrinsic properties and dynamic processes affect energy transfer and defect evolution in irradiated materials. Here we report that chemical disorder, with an increasing number of principal elements and/or altered concentrations of specific elements, in single-phase concentrated solid solution alloys can lead to substantial reduction in electron mean free path and orders of magnitude decrease in electrical and thermal conductivity. The subsequently slow energy dissipation affects defect dynamics at the early stages, and consequentially may result in less deleterious defects. Suppressed damage accumulation with increasing chemical disorder from pure nickel to binary and to more complex quaternary solid solutions is observed. Understanding and controlling energy dissipation and defect dynamics by altering alloy complexity may pave the way for new design principles of radiation-tolerant structural alloys for energy applications.

Highlights

A grand challenge in materials research is to understand complex electronic correlation and non-equilibrium atomic interactions, and how such intrinsic properties and dynamic processes affect energy transfer and defect evolution in irradiated materials
The alloy development and progress represent a major scientific challenge: can we take advantage of property enhancements to go beyond linear extrapolation, to develop a fundamental understanding of energy dissipation mechanisms and to control defect evolution? The long-standing challenge and tangled outcomes from alloy development guide us to focus our work on the early stages of defect dynamics in simple lattice structure with an overarching goal to understand the correlation between intrinsic properties, energy dissipation and defect evolution
We show that chemical disorder and compositional complexity in single-phase concentrated solid solution alloys (SP-CSAs) have an enormous impact on defect dynamics through the substantial modification of energy dissipation pathways

Summary

Introduction

A grand challenge in materials research is to understand complex electronic correlation and non-equilibrium atomic interactions, and how such intrinsic properties and dynamic processes affect energy transfer and defect evolution in irradiated materials. As SP-CSAs possess unique links between intrinsic material properties, energy dissipation and various dynamic processes, they are ideal systems to fill the knowledge gaps between electronic-/atomic-level interactions and radiation resistance mechanisms. By performing ab initio electronic structure calculations, predicting primary damage formation in displacement cascades and lattice thermal conductivity based on molecular dynamics simulations, understanding intrinsic transport properties based on electrical resistivity and total thermal conductivity measurements, and identifying irradiation response utilizing in situ ion channelling technique and high-resolution transmission electron microscopy (TEM), we show that increasing chemical disorder in these model alloys can lead to substantial reduction in the electron mean free path and thermal conductivity. That much slower energy dissipation results in less deleterious defects and consequent slower damage accumulation under ion irradiation

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Results

Conclusion