Au Ion Irradiation Research Articles

Irradiation induced structural damage and evolution of mechanical properties in high entropy fluorite oxide

Pursuing material with excellent irradiation resistance, high chemical durability, and stable mechanical properties under extreme conditions is of great significance for developing irradiation-resistant materials. Herein, a novel irradiation-resistant high-entropy fluorite oxide (Nd0.2Sm0.2Gd0.2Dy0.2Er0.2)2Ce2O7 is reported. After 9-MeV Au ion irradiation with ion fluence of 2.7 × 1015 and 4.5 × 1015 ions/cm2, the high-entropy (Nd0.2Sm0.2Gd0.2Dy0.2Er0.2)2Ce2O7 shows excellent phase stability without phase decomposition and transformation. In comparison with Nd2Ce2O7, the high-entropy (Nd0.2Sm0.2Gd0.2Dy0.2Er0.2)2Ce2O7 possesses much less amorphization and lattice expansion, suggesting its improved irradiation resistance. No pronounced variation in Raman spectra can be detected in the post-irradiated structure, implying rarely structural shift arises in high-entropy (Nd0.2Sm0.2Gd0.2Dy0.2Er0.2)2Ce2O7. After irradiation, there is no irradiation-induced segregation at grain boundaries or inside the grains of high-entropy (Nd0.2Sm0.2Gd0.2Dy0.2Er0.2)2Ce2O7. The nanoindentation tests reveal that the mechanical properties of the high-entropy fluorite oxide rarely degrade. The results, along with the insight into the mechanism of heavy-ion irradiation resistance, provide insight for the subsequent research on the heavy-ion irradiation of high-entropy ceramics.

Change in local structure and hardness in the amorphization process of Zr45Cu45Al10 alloy by heavy ion irradiation

Hypo-eutectic alloy of Zr45Cu45Al10 was irradiated with 16 MeV and 200 MeV Au ions at room temperature. Before and after irradiation, effects of the irradiation on the structure and hardness of the alloy were investigated by using X-ray diffraction (XRD), Extended X-ray absorption fine structure (EXAFS), micro-Vickers hardness and positron annihilation measurements. As a result of the irradiation, amorphization was confirmed for both energies of the irradiations, but the behavior of hardness change strongly depends on the irradiation energy. That is, the hardness once decreases and increases with increasing the fluence in the case of 16 MeV irradiation, but in the case of 200 MeV irradiation, no decreasing trend was observed. The EXAFS measurement shows that the changing ratio of Cu-Cu and Cu-Zr bonds around each Cu atom is different between low energy and high energy Au ion irradiation.

Effect of Au-ion irradiation on the corrosion behavior of CLF-1 steel

The corrosion behavior of the CLF-1 steel irradiated by 6 MeV Au-ions with different fluences was studied by exposing it to a solid tritium breeder (Li4SiO4) in a 0.12 MPa He + 1% H2 atmosphere at 550 °C. The results showed that irradiation-induced hardening appeared in the irradiated CLF-1. The double corrosion layer appeared on the irradiated samples, and the thickness of the corrosion layer increased with the irradiation damage level. A newly formed corrosion product of Li2Fe3O4 appeared on the sample surface corresponding to the highest irradiation damage level. The underlying mechanism for the changed mechanical properties and corrosion products is discussed.

Heavy ion irradiation induced phase transitions and their impact on the switching behavior of ferroelectric hafnia

The discovery of ferroelectric hafnium oxide enabled a variety of non-volatile memory devices, like ferroelectric tunnel junctions or field-effect transistors. Reliable application of hafnium oxide based electronics in space or other high-dose environments requires an understanding of how these devices respond to highly ionizing radiation. Here, the effect of 1.6 GeV Au ion irradiation on these devices is explored, revealing a reversible phase transition, as well as a grain fragmentation process. The collected data demonstrate that non-volatile memory devices based on ferroelectric hafnia layers are ideal for applications where excellent radiation hardness is mandatory.

Au-ion irradiation effects on microstructure and deuterium permeation resistance of Al/Al2O3 coating

Al/Al2O3 coating with a total thickness of approximately 3 μm was irradiated by 6 MeV Au-ions with the damage level from 13 to 39 dpa at room temperature. The results showed that the surface roughness of the Al/Al2O3 coating decreased with increasing irradiation damage levels. As the irradiation damage level is up to 39 dpa, the crystallinity of the Al2O3 layer is enhanced, and the irradiation-induced defects such as voids and dislocations appeared in the Al/Al2O3 coating. The decreased hardness and the deterioration of deuterium permeation resistance are strongly associated with the changed microstructure. The underlying mechanism for the evolution of the microstructure and properties induced by Au-ion irradiation is discussed.

Raman spectroscopy study of damage in swift heavy ion‐irradiated ceramics

AbstractRaman scattering is applied to probe the radiation damage in swift heavy ion‐irradiated ceramics, namely zirconium nitride (ZrN), ceria (CeO2), and yttria‐stabilized zirconia (ZrO2: Y, or YSZ) for about the same high electronic stopping power of heavy ions. Raman spectra show that these ceramics are radiation‐resistant materials that are not amorphized by such irradiations even for large ion track overlap at high fluences. However, for ZrN, the increase of the TA/LA and TO/LO band intensities versus fluence is evidenced after 100‐MeV Xe ion irradiation up to a saturation for the fluence of 3 × 1012 cm−2. The band growths are ascribed to the increase of the concentration of Zr and N vacancies induced by electronic excitations inside tracks. However, the diffuse reflectance spectra do not exhibit any clear modifications of the electronic structure. For ceria, the decrease and broadening of the main F2g peak of the fluorite‐like structure and the growth of a broad defect band assigned to oxygen vacancy formation is observed versus fluence up to 1014 cm−2 for 200‐MeV Xe ion irradiation. For YSZ, Raman spectra mainly give evidence of the intrinsic lattice disorder due to the native oxygen vacancies even up to high fluences of about 3 × 1013 cm−2 for 200‐MeV I and 200‐MeV Au ion irradiation. Results are discussed on the basis of the interplay between the native structural disorder and the radiation‐induced disorder by electronic excitations in these three materials.

Interface evolution and corrosion performance of (TiTaNbZrNi)N HEA coatings with a hybrid architecture under 6 MeV Au-ion irradiation

The coating structure design strategy is one of the important ways to improve the resistance to irradiation damage and corrosion resistance of the accident tolerant fuel (ATF) coating. In this work, the interface evolution and anti-corrosion of the (TiTaNbZrNi)N hybrid structure coating with ν = 1 sccm/min under the irradiation of 6 MeV Au-ions with fluences of 5.8 × 1015 ion/cm2 were investigated. The irradiation results showed that the (TiTaNbZrNi)Nx sublayer of the (TiTaNbZrNi)N hybrid coating disappeared after irradiation, and the three-phase interface of (TiTaNbZrNi)N, (TiTaNbZrNi)Nx and TiTaNbZrNi was transformed into two phase interface of (TiTaNbZrNi)N and TiTaNbZrNi. Moreover, the autoclave corrosion test results indicated that the unirradiated and irradiated coatings have stable FCC structures after corrosion test, and the irradiated coating exhibits lower oxygen penetration depth and better corrosion resistance. The evolution of the coating interface caused by irradiation has a significant impact on the corrosion performance of the coating. This work reveals that the interface evolution of the hybrid structure induced by radiation is beneficial to improve the corrosion resistance of the coating, which has potential application in light water reactor.

Effect of Post-irradiation Annealing on Microstructure Evolution and Hardening in GH3535 Alloy Irradiated by Au Ions

The Au ion-irradiation experiments of GH3535 alloy, a candidate alloy structural material for molten salt reactor, was carried out in this study. Herein, isochronous annealing experiments were conducted from 200 to 850 °C to clarify the evolution behavior of damage defects with increasing temperature. The coarsening of dislocation loops and formation and dissolution of precipitates with increasing annealing temperature were characterized by transmission electron microscopy. Nanoindentation was performed to measure the variation of hardness caused by irradiation. Additionally, the relationship between irradiation hardening and microstructure evolution was established. This study lays a foundation for the evaluation of irradiation damage properties of GH3535 alloy at different annealing temperatures.

Investigation of radiation damage using thermal spike model for SHI irradiation on Al2O3

The material exposed to energetic radiation may change its properties and performance. Ion beam irradiation is an established method to investigate radiation damage in materials. In the present study, SRIM code is employed as a tool to determine the electronic and nuclear energy losses and displacement per atom (DPA) associated with the damage induced in Al2O3 using 100 MeV Au ion. We have further studied the creation of 100 MeV Au ion induced molten zone along the ion track in Al2O3 in the framework of the thermal spike (TS) model. Using the in-elastic thermal spike model, elastic thermal spike model, and unified thermal spike model, the evolution of lattice temperature and latent track radius as a function of depth of Al2O3 for 100 MeV Au ion irradiation are investigated. The current results demonstrate that the latent track radius shows a U-shaped variation based on the combined effect of electronic stopping power and nuclear stopping power. In order to corroborate these results, an additional irradiation experiment was performed using swift heavy ion (SHI), 100 MeV Au ions with fluence 1×1014 ions/cm2 for Al2O3. To investigate the structural properties, surface morphology and to identify the defects in the samples, pristine and irradiated Al2O3 samples were characterized by Grazing Incident X-Ray Diffraction (GIXRD), Atomic Force Microscopy (AFM) and Photoluminescence Spectroscopy (PL). AFM study shows the increase in roughness after SHI irradiation. A decrease in intensity of PL spectra upon SHI irradiation indicates the formation of new defects and disordered structures in the material, which is quite in agreement with the theoretical results.

Surface engineering of poly(methyl methacrylate)–reduced graphene oxide composite films by Au7+ ion irradiation for biomedical application

In this work, PMMA-reduced graphene oxide (rGO) films (PrGO) were prepared by solvent evaporation and further, swift heavy ions (100 MeV gold ion) irradiated on them by varying fluences viz. 1 × 1011, 5 × 1011 and 1 × 1012 ions/cm2 (referred as PrGO-111, PrGO-511, PrGO-112). There was a low angle peak shift of rGO and the reduction of crystallinity at higher fluences. On irradiation, the intensities of the vibrational modes of C–H bonding, hydroxyl, carboxyl groups of rGO and the band gap (36%) are reduced. The surface roughness (69%), pore size (∼10–24 μm), hemocompatibility and contact angle are enhanced on irradiation. The antibacterial efficiency and cell proliferation were augmented on PrGO-511 compared to the other films. The Au ion irradiation tailors surface roughness, contact angle, antibacterial activity and cell proliferation. Further, the atomic local bonding and surface roughness are correlated with the biological properties. Thus, the irradiated PrGO films could be an excellent candidate for applications in the biomedical field.

Effect of Au ion irradiation on the surface morphology, microstructure and mechanical properties of AlNbTiZr medium-entropy alloy coatings with various Al content for ATF

The AlNbTiZr medium-entropy alloy (MEA) coatings with different Al content were irradiated by 6 MeV Au-ions. The effect of the irradiation fluence on the surface morphology, microstructure and mechanical properties of the coatings with different Al content were investigated by SEM, XRD, TEM and nano-indenter. The results showed that the surface of coatings became flatter and smoother with increasing ion irradiation fluence. The crystal structure of all the coatings remained stable at lower fluence. However, the crystallization phenomena occurred at higher irradiation fluence and crystallization degree of the coatings decreased with increasing Al content, which the average crystal size was proportional to the irradiation damage level. The irradiation-induced crystallization changed the uniformity of element distribution, and element segregation phenomenon appeared in the Al-containing coating. The change of coatings hardness after irradiation is related to the amount of free volume content introduced by irradiation and the degree of crystallization. All of these results will help us to understand the response of the AlNbTiZr MEA coatings with different Al content under ion irradiation.

Microstructure response and lead-bismuth eutectic corrosion behavior of 11Cr1Si ferritic/martensitic steel after Au-ion irradiation

The effect of Au-ion irradiation dose on microstructure evolution and lead-bismuth eutectic (LBE) corrosion behavior of 11Cr1Si ferritic/martensitic (F/M) steels was investigated. The results showed that the dislocation loops gradually evolved into dislocation networks with the increase of irradiation dose, and irradiation-induced hardening was also observed. Moreover, irradiation accelerated the F/M steels corrosion in both three doses, and the possible role of irradiation damage on corrosion was also considered.

Effect of Au-ion irradiation on the microstructure and deuterium permeation resistance of the Al2O3 prepared by the MOD method

Al 2 O 3 coatings with a thickness of approximately 500 nm were prepared by the metal-organic decomposition method. An irradiation experiment was performed at room temperature using 6 MeV Au 2+ with irradiation damage of 2, 3 and 5 dpa. The results showed that the surface roughness of the coatings increased with increasing irradiation fluence , and a structural change from amorphous to crystalline γ-Al 2 O 3 was observed. The deuterium permeation resistance of the coatings worsened with increasing of the irradiation fluence. A bubble-like structure appeared on the surface of the irradiated coatings after the deuterium gas-driven permeation (D-GDP) was tested. The microdefects induced by irradiation and the invasion of the deuterium atoms during the D-GDP test could have caused the microstructure evolution and change in deuterium permeation resistance of the coatings. • Al 2 O 3 coatings prepared by the MOD method were irradiated by 6 MeV Au 2+ . • Increased roughness and irradiation-induced crystallization were observed. • Deuterium permeation resistance of the irradiated coatings became worse. • Bubble-like structure appeared on the irradiated coatings after the GDP was tested.

Enhanced recombination suppresses the void swelling in bcc multi-component alloys

Multi-component alloys, e.g., high-entropy alloys, exhibit excellent mechanical and radiation tolerance properties, making them potential candidate materials in nuclear applications. In this work, the void swelling in a single-phase body-centered cubic (bcc) reduced activation multi-component alloy FeCrV under high dose Au-ion irradiation was investigated. It is found that FeCrV has a significantly suppressed void swelling compared to α-Fe, with voids of smaller size distributed in a narrower region. To understand the difference between these two alloys in the defect evolution and its possible effect on the void swelling, the diffusion of point defects in α-Fe and FeCrV was investigated. Combined Density Functional Theory (DFT) and kinetic Monto Carlo (kMC) method based on the environment-dependent vacancy migration energies was used to simulate the vacancy diffusion. It is shown that vacancy diffusion is enhanced, which is because vacancies prefer to migrate through the easy migration channels which have lower values of the wide migration energy distribution in multi-component alloys. Ab initio molecular dynamics (AIMD) was employed to simulate the interstitial diffusion. The results show the interstitial diffusion is sluggish in FeCrV due to the atomic traps existing that slow down interstitials’ migration. The migration process of point defects in bcc multi-component alloy shows clear chemical environment dependence. The closer mobilities of vacancies and interstitials enhance the local recombination of point defects and suppress the void swelling.

Effect of Au-ions irradiation on mechanical and LBE corrosion properties of amorphous AlCrFeMoTi HEA coating: Enhanced or deteriorated?

The effect of Au-ions irradiation with different damage doses from 10 to 90 dpa on mechanical properties and LBE corrosion behavior of AlCrFeMoTi HEA coating was investigated. The fracture toughness and the interface bonding strength had been improved after irradiation. The Au-ions irradiation decelerated LBE corrosion rate of coating at low damage dose, which could be attributed to the formation of a more continuous Cr2O3 layer adjacent to the coating surface. However, the element diffusion was intensified and the Cr2O3 layer became more thick and porous at high damage dose, which resulted in the acceleration of LBE corrosion.

Corrosion behavior of ion-irradiated 12Cr2W2Mn F/M steel in liquid LBE

The corrosion characteristics of 12Cr2W2Mn Ferritic/martensitic (F/M) steel before and after Au-ions irradiation in static lead–bismuth eutectic (LBE) have been investigated at 400 °C for 100 h. The results show that the samples without irradiation have many unequal size Fe3O4 particles and little Cr-rich oxide after LBE corrosion test, and the thickness of corrosion layer is 4.4 μm. The irradiation samples display plenty compact triangular (Fe,Cr)3O4 and some Cr-rich oxide, and the thickness of corrosion layer is 4.4 μm with some cracks. Au-ions irradiation enahnced the LBE corrosion of F/M steel, which could be attributed to the irradiation defects provide diffusion path of O atoms in liquid LBE. A schematic model was presented to understand the effect of irradiation damage on LBE corrosion behavior of F/M steel.

SURFACE MODIFICATION OF COMMERCIALLY PURE TITANIUM BY GOLD-ION IRRADIATION FOR BIOMEDICAL APPLICATIONS

This research work’s aim was to enhance the biocompatibility of the commercially pure titanium (cpTi-2) surface via Au-ion irradiation. Various ion dosages, i.e. [Formula: see text] (Au-11), [Formula: see text] (Au-12) and [Formula: see text] (Au-13) ions[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text], were produced by exposing the polished cpTi-2 samples to Au-ion beam at room temperature. The surface topographic features of cpTi-2 and the effects of Au-ion-implanted surfaces were examined by atomic force microscopy and XRD analysis. Open-Circuit Potential (OCP), Potentiodynamic Polarization Scans (PPS) and Electrochemical Impedance Spectroscopy (EIS) were used to compare the electrochemical behavior of the cpTi-2 and Au-ion-implanted samples in Ringer’s lactate (RL) solution at 37∘C. The effects of Au-ion irradiation on the proliferation of mesenchymal stem cells (MSCs) were estimated during 24[Formula: see text]h and 48[Formula: see text]h of exposure. Based on the experimental results, Au-12 samples presented more positive OCP and lower corrosion rate in RL solution than the Au-11 and Au-13 samples. No significant change in the morphology of the MSCs was observed after exposure to the Au-ion-implanted samples. Similar to the controlled medium, the percentage of viability of the cells of the cells on Au-12 increased from 75% to 165% on the surface of Au-13 samples during 48[Formula: see text]h of incubation indicating the positive effects of Au-ion irradiation for biocompatibility.

Effect of Au-ion irradiation on the surface morphology, microstructure and mechanical properties of amorphous AlCrFeMoTi HEA coating

The amorphous AlCrFeMoTi high-entropy alloy (HEA) coating with near-equal molar ratio was successfully deposited on F/M substrate by magnetron co-sputtering technique and then was irradiated by 6 MeV Au ions with different irradiation damage doses from 10 dpa to 90 dpa. XRD, SEM, AFM, TEM and nanoindentation tests were carried out to investigate the surface morphology, microstructure and hardening effect of the coating. The results showed that the coating surface became more featureless after irradiation, where the surface roughness decreased with increasing damage doses. The crystallization phenomena occurred in amorphous AlCrFeMoTi coatings at high irradiation damage doses (45 dpa and 90 dpa), where the crystallization zone were much closer to the coating surface than the calculated peak damage region. However, the irradiation-induced crystallization did not obviously change the uniformity of elements distribution. Meanwhile, the irradiation hardening effect can be observed, and the nanohardness of the coating increased with increasing damage doses. The AlCrFeMoTi HEA coating exhibits excellent ion-irradiation resistance and has potential applications in lead cooled fast reactor. Meanwhile, this work can help us to further investigate the performance of the AlCrFeMoTi HEA coating in the coupled environment of irradiation and corrosion, and evaluate its serviceability.

Irradiation Behaviors in BCC Multi-Component Alloys with Different Lattice Distortions

Recently, the irradiation behaviors of multi-component alloys have stimulated an increasing interest due to their ability to suppress the growth of irradiation defects, though the mostly studied alloys are limited to face centered cubic (fcc) structured multi-component alloys. In this work, two single-phase body centered cubic (bcc) structured multi-component alloys (CrFeV, AlCrFeV) with different lattice distortions were prepared by vacuum arc melting, and the reference of α-Fe was also prepared. After 6 MeV Au ions irradiation to over 100 dpa (displacement per atom) at 500 °C, the bcc structured CrFeV and AlCrFeV exhibited significantly improved irradiation swelling resistance compared to α-Fe, especially AlCrFeV. The AlCrFeV alloy possesses superior swelling resistance, showing no voids compared to α-Fe and CrFeV alloy, and scarce irradiation softening appears in AlCrFeV. Owing to their chemical complexity, it is believed that the multi-component alloys under irradiation have more defect recombination and less damage accumulation. Accordingly, we discuss the origin of irradiation resistance and the Al effect in the studied bcc structured multi-component alloys.

Ion irradiation induced strain and structural changes in LiTaO3 perovskite* *This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the

LiTaO3 crystals irradiated with 3 MeV and 1.162 GeV Au ions were studied by single crystal x-ray diffraction and Raman scattering measurements. The maximum lattice strains after 3 MeV Au ion irradiation to a fluence of 1.2 × 1013 cm−2 were 1.2% and 0.6% along the c- and a-/b-axes, respectively. Two effects were observed in 1.162 GeV Au ion irradiated samples: (i) the (0006) and (1120) Bragg peaks were split into doublets, which suggested a subtle structural change due to slight modification of chemical composition; and (ii) the pre-damaged 1.2% lattice strain along the c-axis was relaxed to 0.9% after subsequent irradiation with 1.162 GeV Au ions, while relaxation along the a- or b-axis was not obvious. A distinct change in the Raman spectrum of the 〈0001〉 oriented LiTaO3 crystals was observed after 1.162 GeV Au ion irradiation, but no obvious change was observed in the 〈1120〉 oriented samples or in 3 MeV Au ion irradiated samples. Strain and structural changes in crystalline LiTaO3, with or without pre-existing defects, upon ion irradiation are delineated in its responding to inelastic ionization and elastic nuclear collisions.