Monolayer-thick TiO precipitation in V-4Cr-4Ti alloy induced by proton irradiation

Abstract

We have characterised to atomic resolution the mono-layer thick TiO-type precipitate induced by proton irradiation in V-4Cr-4Ti alloy at the coarsening radiation-induced interstitial a/2⟨111⟩ dislocation loops expected to exert a minimal effect on the precipitate formation. This monolayer-thick precipitate constitutes an early stage in the radiationinduced aging process of V-4Cr-4Ti at low temperatures, and can potentially absorb additional light elements in reactor environments. 1Moor Row, November 24, 2016 Dear Prof. Beyerlein, Please find attached the resubmitted manuscript SMM-16-1716 entitled 'Monolayer-thick TiO precipitation in V-4Cr-4Ti alloy induced by proton irradiation' which has been significantly revised on the basis of the comments received by the reviewers.The detailed response to the reviewers' comments, together with the revised version of the manuscript, is attached. We would like to thank the reviewers for their time and effort in appraising the manuscript. The comments received were pertinent and helpful in improving the manuscript. All the points raised have been addressed and the manuscript has been amended accordingly. We believe that the revisions made adequately address the points raised and should therefore present no further obstacle to publication. We thank the reviewers for carefully reading the manuscript and the useful comments. We have addressed all those comments, which we feel have improved the article's quality.Detailed response:1.) In figure 2, images for SA and SACW irradiated at 350C are necessary for better understanding of temperature effects. We have included additional text in the manuscript about the temperature effect. The novelty and impact of this work lies in the recovery of the CWed structure already at 300°C (Fig. 2) before the formation of monolayer-thick RIPs at 350°C (Fig. 3). 2.) What is the relationship between the observed microstructure and the hardness? For example, for SA irradiated at 300C and 350C, where does the difference in hardening come?We have added some text to clarify the observed hardening behaviour at different temperatures in terms of the observed microstructure. 3.) As the observed RIPs in this study is platelet, the description as "average size" may mislead.We have changed the average size of the monolayer-thick RIPs by their average length. 4.) The description about recovery of the pre-existing dislocation network in SACW is contradicting in page 6 and page 7.We have clarified the contradiction in page 6 and 7. 5.) Direct comparison with the results of neutron-irradiation might be difficult since the damage rate is exceedingly large.We have added some text about the difference in dose rate and particle fluence between neutron and proton irradiation. The formation and evolution of a/2 ⟨111⟩ unfaulted dislocation loops in our proton irradiated samples correspond to the observations reported in neutron-irradiated material. However the average loop size at 350C in the proton irradiated samples (85nm) is lower than the value repo...

Irradiation Hardening Behavior of He-Irradiated V–Cr–Ti Alloys with Low Ti Addition

“…Small precipitates formed near the grain boundary or large bulk precipitates and the precipitate was Ti(CON) titanium-oxycarbonitride precipitate on a habit pane of {100}. The nature of the Ti(CON) precipitate has been reported by Impagnatiello [21][22][23]. In the thermal creep test, it is likely that Ti(CON) precipitates are formed along with defect sinks such as grain boundaries and bulk precipitates where the thermal vacancy is absorbed preferentially.…”

A review of solute-point defect interactions in vanadium and its alloys: first-principles modeling and simulation

“…These results show that these impurities strongly affect the clustering of He in vacancies and the stability of the He n -vacancy type clusters. More recently, Impagnatiello et al [34][35][36] characterized the precipitate of V-4Cr-4Ti by proton irradiation at low temperature using high-resolution electron microscopy. They confirmed that the monolayer-thick TiO precipitate constitutes an early stage in the irradiation-induced aging process of V-4Cr-4Ti and the TiO-precipitate has a NaCltype structure.…”

Resurgence of a Nation’s Radiation Science Driven by Its Nuclear Industry Needs

“…Heavy ions are of particular interest in radiation damage studies as although their range in a material is limited, they create large amounts of damage in their short path. Some of these studies include candidate materials for plasma-facing walls and structural materials in fusion reactors [14][15][16][17], structural components for fuel assemblies inside nuclear cores [18,19], as well as investigation of potential new materials for use in such extreme environments [20,21].…”