A comprehensive study on the impact of He ion irradiation on the microstructure and mechanical properties of a Ni-Cr-Mo alloy

Abstract The impact of helium ion irradiation on the evolution of microstructure and mechanical properties of a Ni-45%Cr-1.4%Mo (wt%) alloy has been investigated. Analysis via transmission electron microscopy (TEM) of a pristine sample revealed an uneven distribution of alpha-Cr phase precipitates a...

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Main Authors: Sanjay Saini, Ranjini Menon, S. K. Sharma, P. Y. Nabhiraj, Suman Neogy, A. P. Srivastava
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-11922-x
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Summary:Abstract The impact of helium ion irradiation on the evolution of microstructure and mechanical properties of a Ni-45%Cr-1.4%Mo (wt%) alloy has been investigated. Analysis via transmission electron microscopy (TEM) of a pristine sample revealed an uneven distribution of alpha-Cr phase precipitates along with a few isolated planar arrangements of dislocations within the fcc γ-Ni matrix phase. A detailed study of irradiated samples established the presence of radiation-induced defect clusters, dislocation loops, network dislocations as perceptible irradiation effects. X-ray diffraction (XRD) and positron annihilation spectroscopy (PAS) studies also confirmed lattice swelling as an effect of irradiation in this alloy, likely caused by helium-stabilized vacancy cluster. A line profile analysis method which takes into account of planar defects, was employed on GIXRD (Grazing Incidence X-ray Diffraction) data to analyze changes in microstructural parameters such as domain size, microstrain, dislocation density and lattice parameter as a function of irradiation dose. All of these irradiation-damage manifestations led to the increase in the hardness of the alloy in nano-indentation experiment. Overall, the findings of this work provide significant insights into the radiation-induced microstructural changes and their effect on the hardening behavior of the studied Ni-Cr-Mo alloy.
ISSN:2045-2322