Temperature effect on irradiation damage in equiatomic multi-component alloys

Emil Levo,Fredric Granberg,Kai Nordlund,Flyura Djurabekova

doi:10.1016/j.commatsci.2021.110571

Emil Levo, Fredric Granberg + Show 2 more

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https://doi.org/10.1016/j.commatsci.2021.110571

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Abstract

Multiprincipally designed concentrated solid solution alloys, such as high entropy alloys (HEA) and equiatomic multi-component alloys (EAMC-alloys) have shown much promise for use as structural components in future nuclear energy production concepts. The irradiation tolerance in these novel alloys has been shown to be superior to that in more conventional metals used in current nuclear reactors. However, studies involving irradiation of HEAs and EAMC-alloys have usually been performed at room temperature. Hence, in this study the irradiation damage is investigated computationally in two different Ni-based EAMC-alloys and pure Ni at four different temperatures, ranging from 138 K to 800 K. The irradiation damage was studied by analyzing point defects, defect cluster sizes and dislocation networks in the materials. Dislocation loop mobility calculations were performed to help understanding the formation of different dislocation networks in the irradiated materials. Utilizing the knowledge of the depth distribution of damage, and using simulations of Rutherford backscattering in channeling conditions (RBS/c), we can relate our results to experimental data. The main findings are that the alloys have superior irradiation tolerance at all temperatures as compared to pure Ni, and that the damage is reduced in all materials with an increase in temperature.

Highlights

New advancements in energy production, such as generation nuclear reactors, have increased the need to develop novel materials able to withstand demanding operational environments in which high irradiation doses, high temperatures and corrosion risks are common place
Point defect concentration In Refs. 2 and 4 the point defect accumulation was compared at 300 K between different EAMC-alloys and pure Ni
At the higher temperatures (500 and 800 K) where the alloys definitely perform better than pure Ni, it is unclear whether NiFe or NiCoCr performs best in terms of lower defect accumulation

Summary

Introduction

New advancements in energy production, such as generation nuclear reactors, have increased the need to develop novel materials able to withstand demanding operational environments in which high irradiation doses, high temperatures and corrosion risks are common place. The irradiation resistance in Ni-based HEAs and EAMC-alloys has been studied both experimentally and computationally [6,7,8,2,3,9,4,10,5], with some of the results concluding that the alloys exhibit a heightened tolerance against irradiation when compared to pure Ni. Being subject to high irradiation doses and high temperatures, the effect which different temperature has on the damage accumulation in HEAs should be investigated. The studies of the tem perature dependence to date have been experimental [7,11,12,13] These works have for instance shown that NiFe outperforms NiCoCr, in terms of irradiation tolerance, at temperatures above 300 K, while at tem peratures below or equal to 300 K, the behaviour is opposite [11]

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