Effect of dose rate on the characteristics of dislocation loops in palladium: In-situ TEM analysis during 30 keV H2+ irradiation. (1st July 2023)

• Record Type: Journal Article
• Authors: Cui, Dewang; Cao, Ziqi; Ding, Yifan; Li, Yipeng; Ran, Guang
• Is Part Of: Journal of materials science & technology. Volume 150(2023)
• Page Start: 86
• Page End: 95
• Publication Date: 2023-07-01
• Subjects: Palladium -- Hydrogen irradiation -- In-situ TEM observation -- Dislocation loop -- Dose rate; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2022.12.013
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: Effect of dose rate on loop characteristics was studied in situ during H2 + irradiation. Dose rate obviously affected the nucleation rate, growth rate, and types of loops. High dose rate induced high density, small average size, and low growth rate of loops. High dose rate caused low irradiation hardening and damage induced by loops. High dose rate was beneficial to the generation of perfect dislocation loops. Abstract: Ion irradiation is usually used to simulate neutron irradiation to accelerate the evaluation of the irradiation behavior of reactor materials. However, the validity of using a high damage rate of ion irradiation to simulate a low damage rate of neutron irradiation has always been a controversial topic. Here, the effect of two dose rates (2.94 × 10 –6 and 7.35 × 10 –5 dpa s –1 ) on the characteristics and evolution of dislocation loops in palladium was studied in situ during 30 keV H2 + irradiation using transmission electron microscopy. The dose rate obviously affected the nucleation rate and growth rate of dislocation loops, the types (Frank loops or perfect loops) of dislocation loops, and the irradiation hardening and total damage obtained from the product of average loop size and loop density. At the same irradiation dose, a high dose rate would lead to high loop density, small average loop size, low loop growth rate, and low irradiation hardening and damage induced by loops in pure Pd. Meanwhile, it was found for the first time that a high dose rate was beneficial to the generation of perfect dislocation loops. The effect of dose rate was attributed to the different dynamic equilibrium results between the effective generation rate of point defects and their absorption rate by existing sinks. The present results show that the effect of dose rate should be considered when using ion irradiation to simulate neutron irradiation to evaluate the irradiation damage to materials.