Pub Date : 2024-11-05DOI: 10.1016/j.jnucmat.2024.155500
Yunya Dai , Xiaoyuru Chen , Bo Liao , Fu Wang , Hanzhen Zhu , Qilong Liao , Liyuan Dong , Jinlan Nie
The properties of (Ti1-xZrx)3SiC2 (x = 0, 0.04, 0.06, 0.09, 0.13, and 0.17) and the behavior of helium within (Ti1-xZrx)3SiC2 were investigated through first-principles calculations. It was found that the (Ti1-xZrx)3SiC2 ceramics are all thermodynamically stable, while their thermal stability decreases as the Zr content increases. Additionally, the substitution of Zr for Ti results in a lattice expansion of the system. It was observed that helium tends to occupy the interstitial sites near the Si layer in (Ti1-xZrx)3SiC2. As the concentration of Zr increases, the interaction between helium and surrounding atoms weakens, leading to a higher solubility of helium in (Ti1-xZrx)3SiC2. Furthermore, with increasing Zr concentration, the diffusion energy barrier for interstitial helium gradually increases. This likely results in greater difficulty for helium migration, thus enhancing the stability of this material. Therefore, it is concluded that substituting Zr for Ti is one of the beneficial ways to enhance the radiation resistance of Ti3SiC2.
{"title":"The behavior of Helium in (Ti1-xZrx)3SiC2 by first-principles study","authors":"Yunya Dai , Xiaoyuru Chen , Bo Liao , Fu Wang , Hanzhen Zhu , Qilong Liao , Liyuan Dong , Jinlan Nie","doi":"10.1016/j.jnucmat.2024.155500","DOIUrl":"10.1016/j.jnucmat.2024.155500","url":null,"abstract":"<div><div>The properties of (Ti<sub>1-</sub><em><sub>x</sub></em>Zr<em><sub>x</sub></em>)<sub>3</sub>SiC<sub>2</sub> (<em>x</em> = 0, 0.04, 0.06, 0.09, 0.13, and 0.17) and the behavior of helium within (Ti<sub>1-</sub><em><sub>x</sub></em>Zr<em><sub>x</sub></em>)<sub>3</sub>SiC<sub>2</sub> were investigated through first-principles calculations. It was found that the (Ti<sub>1-</sub><em><sub>x</sub></em>Zr<em><sub>x</sub></em>)<sub>3</sub>SiC<sub>2</sub> ceramics are all thermodynamically stable, while their thermal stability decreases as the Zr content increases. Additionally, the substitution of Zr for Ti results in a lattice expansion of the system. It was observed that helium tends to occupy the interstitial sites near the Si layer in (Ti<sub>1-</sub><em><sub>x</sub></em>Zr<em><sub>x</sub></em>)<sub>3</sub>SiC<sub>2</sub>. As the concentration of Zr increases, the interaction between helium and surrounding atoms weakens, leading to a higher solubility of helium in (Ti<sub>1-</sub><em><sub>x</sub></em>Zr<em><sub>x</sub></em>)<sub>3</sub>SiC<sub>2</sub>. Furthermore, with increasing Zr concentration, the diffusion energy barrier for interstitial helium gradually increases. This likely results in greater difficulty for helium migration, thus enhancing the stability of this material. Therefore, it is concluded that substituting Zr for Ti is one of the beneficial ways to enhance the radiation resistance of Ti<sub>3</sub>SiC<sub>2</sub>.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155500"},"PeriodicalIF":2.8,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-04DOI: 10.1016/j.jnucmat.2024.155498
Hanns Gietl , Chase N. Taylor , Yuji Hatano , Yasuhisa Oya , Masashi Shimada
The effect of mixed spectra and thermal neutron shielded irradiation on tungsten was evaluated with plasma exposure in the tritium plasma experiment followed by thermal desorption spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The two different irradiation campaigns were performed at the High Flux Isotope Reactor to 0.39–0.74 displacement per atom (dpa) in the 894–1379 K temperature range. A neutron spectrum influence on the void size and void number density was not observed. However, a strong correlation was found between void size and void number density with temperature, but not with dpa in the limited dpa range of this study. Thermal neutron shielding significantly reduced the transmutation to Re+Os. Higher irradiation temperature will lead to larger voids with lower number density, which reduces deuterium retention. Grain growth was also observed for high-temperature irradiation of over ∼1300 K within the limited grains visible in the transmission electron microscopy specimens.
在氚等离子体实验中，通过等离子体照射评估了混合光谱和热中子屏蔽辐照对钨的影响，随后进行了热解吸光谱分析、X 射线光电子能谱分析和透射电子显微镜分析。在 894-1379 K 的温度范围内，在高通量同位素反应堆进行了两种不同的辐照活动，每原子位移 (dpa) 在 0.39-0.74 之间。没有观察到中子谱对空隙大小和空隙数密度的影响。然而，在本研究有限的 dpa 范围内，空隙尺寸和空隙数密度与温度之间存在很强的相关性，但与 dpa 无关。热中子屏蔽大大降低了向 Re+Os 的嬗变。辐照温度越高，空隙越大，空隙数密度越低，从而减少了氘的保留。在透射电子显微镜试样中可见的有限晶粒内，超过 1300 K 的高温辐照也观察到了晶粒生长。
{"title":"Comparative characterization of mixed spectra and thermal neutron shielded irradiated tungsten","authors":"Hanns Gietl , Chase N. Taylor , Yuji Hatano , Yasuhisa Oya , Masashi Shimada","doi":"10.1016/j.jnucmat.2024.155498","DOIUrl":"10.1016/j.jnucmat.2024.155498","url":null,"abstract":"<div><div>The effect of mixed spectra and thermal neutron shielded irradiation on tungsten was evaluated with plasma exposure in the tritium plasma experiment followed by thermal desorption spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The two different irradiation campaigns were performed at the High Flux Isotope Reactor to 0.39–0.74 displacement per atom (dpa) in the 894–1379 K temperature range. A neutron spectrum influence on the void size and void number density was not observed. However, a strong correlation was found between void size and void number density with temperature, but not with dpa in the limited dpa range of this study. Thermal neutron shielding significantly reduced the transmutation to Re+Os. Higher irradiation temperature will lead to larger voids with lower number density, which reduces deuterium retention. Grain growth was also observed for high-temperature irradiation of over ∼1300 K within the limited grains visible in the transmission electron microscopy specimens.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155498"},"PeriodicalIF":2.8,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-03DOI: 10.1016/j.jnucmat.2024.155497
Tanvi Ajantiwalay , Brandon Bohanon , Patrick H. Warren , Megha Dubey , Yaqiao Wu , Janelle P. Wharry , Assel Aitkaliyeva
Nano-compression and nano-tensile tests were used to investigate the behavior of HT-9 steel neutron irradiated to 4.29 dpa at 469 °C. The deformation of both as-received and neutron irradiated HT-9 was monitored in situ with a transmission electron microscope, which allowed linking microstructure of the material with the evolution of mechanical properties and identifying the mechanisms governing irradiation-induced hardening of these steels. In nano-compression tests, dislocation-mediated deformation is the deformation mechanism in HT-9 steels irradiated at elevated temperatures. In nano-tensile tests, while dislocations contribute to hardening, grain boundaries determine the deformation mechanisms and eventual fracture of HT-9. The paper further examines the size effect for nano-mechanical tests by varying sample dimensions and comparing obtained results to the micro- and bulk-scale mechanical test data.
{"title":"Observations of the irradiation hardening behavior in neutron irradiated HT-9 steels through in situ TEM nano-mechanical tests","authors":"Tanvi Ajantiwalay , Brandon Bohanon , Patrick H. Warren , Megha Dubey , Yaqiao Wu , Janelle P. Wharry , Assel Aitkaliyeva","doi":"10.1016/j.jnucmat.2024.155497","DOIUrl":"10.1016/j.jnucmat.2024.155497","url":null,"abstract":"<div><div>Nano-compression and nano-tensile tests were used to investigate the behavior of HT-9 steel neutron irradiated to 4.29 dpa at 469 °C. The deformation of both as-received and neutron irradiated HT-9 was monitored in situ with a transmission electron microscope, which allowed linking microstructure of the material with the evolution of mechanical properties and identifying the mechanisms governing irradiation-induced hardening of these steels. In nano-compression tests, dislocation-mediated deformation is the deformation mechanism in HT-9 steels irradiated at elevated temperatures. In nano-tensile tests, while dislocations contribute to hardening, grain boundaries determine the deformation mechanisms and eventual fracture of HT-9. The paper further examines the size effect for nano-mechanical tests by varying sample dimensions and comparing obtained results to the micro- and bulk-scale mechanical test data.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155497"},"PeriodicalIF":2.8,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1016/j.jnucmat.2024.155493
A. Georgesco , J.-P. Crocombette , G. Gutierrez , C. Onofri , M. Khafizov
To investigate the effect of electronic energy losses on nuclear damage in UO2, we use a simple Rate Theory (RT) model, based on the time evolution of single point defects, governed by their absorption at the surface of TEM lamellae, and by interstitial-type dislocation loops nucleation, solely characterized by their number and average size. We first parametrize the model by fitting six different experimental datasets at various temperatures, ion type and energy (0.39 MeV Xe and 4 MeV Au ion irradiations at 93, 298 and 873 K) where defect evolution in UO2 is dominated by displacement damage caused by nuclear energy losses. The model suggests that dislocation evolution kinetics is driven by monomers diffusion at 873 K. At lower temperature (93 and 298 K) monomer diffusion has little impact and the evolution is governed by the nucleation of loops within the collision cascade. Analysis of four additional experimental datasets at 93 and 298 K where electronic energy losses are strong (single 6 MeV Si and dual simultaneous Xe & Si ion irradiations) required modification of monomer's diffusion coefficients. In the case of single Si ion irradiation, evolution is temperature independent and the enhanced diffusion due to electronic excitations and ionizations are best captured by adding athermal component to the monomer diffusion coefficients. In case of the dual Xe & Si ions irradiation, electronic excitation caused by Si ions impacts the defects pre-generated by Xe ions and enhances defect diffusion by at local heating induced by the thermal spike of Si ions. This effect is best captured by artificially raising the irradiation temperature.
为了研究电子能量损失对二氧化铀核损伤的影响，我们使用了一个简单的速率理论（RT）模型，该模型基于单点缺陷的时间演化，由其在TEM薄片表面的吸收和间隙型位错环核（仅以其数量和平均尺寸为特征）决定。我们首先通过拟合不同温度、离子类型和能量（93、298 和 873 K 下的 0.39 MeV Xe 和 4 MeV Au 离子辐照）下的六个不同实验数据集，对模型进行了参数化。在较低温度下（93 和 298 K），单体扩散的影响很小，缺陷演化受碰撞级联内的环状成核的支配。在 93 和 298 K 温度下，电子能量损失较大（单次 6 MeV Si 和双次同时 Xe & ；Si 离子辐照），对另外四个实验数据集的分析需要修改单体扩散系数。在单硅离子辐照的情况下，演化与温度无关，电子激发和电离导致的扩散增强可通过在单体扩散系数中加入热分量得到最好的捕捉。在氙和amp; 硅离子双重辐照的情况下，硅离子引起的电子激发会影响氙离子预先产生的缺陷，并通过硅离子热尖峰引起的局部加热来增强缺陷扩散。人为地提高辐照温度最能体现这种效果。
{"title":"Rate theory model of irradiation effects in UO2: Influence of electronic energy losses","authors":"A. Georgesco , J.-P. Crocombette , G. Gutierrez , C. Onofri , M. Khafizov","doi":"10.1016/j.jnucmat.2024.155493","DOIUrl":"10.1016/j.jnucmat.2024.155493","url":null,"abstract":"<div><div>To investigate the effect of electronic energy losses on nuclear damage in UO<sub>2</sub>, we use a simple Rate Theory (RT) model, based on the time evolution of single point defects, governed by their absorption at the surface of TEM lamellae, and by interstitial-type dislocation loops nucleation, solely characterized by their number and average size. We first parametrize the model by fitting six different experimental datasets at various temperatures, ion type and energy (0.39 MeV Xe and 4 MeV Au ion irradiations at 93, 298 and 873 K) where defect evolution in UO<sub>2</sub> is dominated by displacement damage caused by nuclear energy losses. The model suggests that dislocation evolution kinetics is driven by monomers diffusion at 873 K. At lower temperature (93 and 298 K) monomer diffusion has little impact and the evolution is governed by the nucleation of loops within the collision cascade. Analysis of four additional experimental datasets at 93 and 298 K where electronic energy losses are strong (single 6 MeV Si and dual simultaneous Xe & Si ion irradiations) required modification of monomer's diffusion coefficients. In the case of single Si ion irradiation, evolution is temperature independent and the enhanced diffusion due to electronic excitations and ionizations are best captured by adding athermal component to the monomer diffusion coefficients. In case of the dual Xe & Si ions irradiation, electronic excitation caused by Si ions impacts the defects pre-generated by Xe ions and enhances defect diffusion by at local heating induced by the thermal spike of Si ions. This effect is best captured by artificially raising the irradiation temperature.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155493"},"PeriodicalIF":2.8,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1016/j.jnucmat.2024.155495
Chinthaka M. Silva , Kyle J. Kondrat , Bradley C. Childs , Maryline G. Ferrier , Michelle M. Greenough , Kiel S. Holliday , Scott J. McCormack
The synthesis of UC using carbothermic reduction of UO2 and C mixtures has been well studied at high temperatures. However, the product phase behavior of carbothermic reduction at low temperatures (≤1773 K) is not well studied. Such a study is important as low temperatures permit single phase UC synthesis without forming secondary higher carbides, and it further supports the knowledge base of the process that needs to be used for transuranic elements such as plutonium that have high vapor pressures at elevated temperatures. Therefore, a low temperature carbothermic reduction of two different C/UO2 molar ratios under inert and reducing environments have been studied here. Two different sample holding crucibles, alumina (Al2O3) and graphite, were also used here to differentiate the hypostoichiometric (UC1-a) and oxygen dissolved (UC1-xOx) uranium monocarbide phases adding more details on the two systems. Also, the reaction kinetics involved in the formation of UC via the carbothermic reduction of UO2+C using product phases instead of evolved gases such as carbon monoxide is reported here. Under inert atmospheres but with significant oxygen partial pressures, the low temperature carbothermic reduction of UO2+C produced up to 90 wt.% UC1-xOx type oxycarbides as was confirmed by Xray powder diffraction. Reducing Ar-4%H2 environments at these temperatures were not successful in synthesizing UC as it reduces the amount of C required for the carbothermic reduction, leaving UC phase at a non-equilibrium state. Inert atmospheres with low or negligible oxygen partial pressures on the other hand produced near stoichiometric UC at high phase purity, especially at 1673 – 1773 K temperature range. An activation energy of 377±75 kJmol-1 was also calculated using product phase concentrations of the carbothermic reduction of UO2+C under these inert Ar(g) atmospheres.
{"title":"On the product phases and the reaction kinetics of carbothermic reduction of UO2+C at relatively low temperatures","authors":"Chinthaka M. Silva , Kyle J. Kondrat , Bradley C. Childs , Maryline G. Ferrier , Michelle M. Greenough , Kiel S. Holliday , Scott J. McCormack","doi":"10.1016/j.jnucmat.2024.155495","DOIUrl":"10.1016/j.jnucmat.2024.155495","url":null,"abstract":"<div><div>The synthesis of UC using carbothermic reduction of UO<sub>2</sub> and C mixtures has been well studied at high temperatures. However, the product phase behavior of carbothermic reduction at low temperatures (≤1773 K) is not well studied. Such a study is important as low temperatures permit single phase UC synthesis without forming secondary higher carbides, and it further supports the knowledge base of the process that needs to be used for transuranic elements such as plutonium that have high vapor pressures at elevated temperatures. Therefore, a low temperature carbothermic reduction of two different C/UO<sub>2</sub> molar ratios under inert and reducing environments have been studied here. Two different sample holding crucibles, alumina (Al<sub>2</sub>O<sub>3</sub>) and graphite, were also used here to differentiate the hypostoichiometric (UC<sub>1-a</sub>) and oxygen dissolved (UC<sub>1-x</sub>O<sub>x</sub>) uranium monocarbide phases adding more details on the two systems. Also, the reaction kinetics involved in the formation of UC via the carbothermic reduction of UO<sub>2</sub>+C using product phases instead of evolved gases such as carbon monoxide is reported here. Under inert atmospheres but with significant oxygen partial pressures, the low temperature carbothermic reduction of UO<sub>2</sub>+C produced up to 90 wt.% UC<sub>1-x</sub>O<sub>x</sub> type oxycarbides as was confirmed by Xray powder diffraction. Reducing Ar-4%H<sub>2</sub> environments at these temperatures were not successful in synthesizing UC as it reduces the amount of C required for the carbothermic reduction, leaving UC phase at a non-equilibrium state. Inert atmospheres with low or negligible oxygen partial pressures on the other hand produced near stoichiometric UC at high phase purity, especially at 1673 – 1773 K temperature range. An activation energy of 377±75 kJmol<sup>-1</sup> was also calculated using product phase concentrations of the carbothermic reduction of UO<sub>2</sub>+C under these inert Ar<sub>(g)</sub> atmospheres.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155495"},"PeriodicalIF":2.8,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jnucmat.2024.155491
Ziwei Li , Dmitry Terentyev , Stefan Holmström , Thomas Pardoen
Screening and qualification of new nuclear materials with superior irradiation resistance requires expensive irradiation exposure and post-irradiation examination before consideration into industrial nuclear structural components. The development of miniaturized test methods is needed for enhanced cost/time efficient testing, while enabling comparative and robust material property estimation in a timely and high throughput manner. The Small Punch Test (SPT) is drawing much interest, especially since the publication of an European standard. Motivated by this standard, a new SP test sample geometry is proposed in order to reduce the material volume to be tested, hences increasing the number of samples that can be introduced in an irradiation rig. The modified sample diameter has been reduced from 8 to 5.35 mm. The qualification of this new design is described here together with a detailed description of the SPT setup modification as compared to the reference setup of the EN standard. Finite element analyses and a series of experiments have been conducted using both standard and reduced size SP samples to demonstrate that the modified test gives estimates of the basic mechanical properties with the same magnitude of error and validates the modified sample geometry for usage in irradiated material testing.
{"title":"Small punch test size reduction to enable high flux irradiation","authors":"Ziwei Li , Dmitry Terentyev , Stefan Holmström , Thomas Pardoen","doi":"10.1016/j.jnucmat.2024.155491","DOIUrl":"10.1016/j.jnucmat.2024.155491","url":null,"abstract":"<div><div>Screening and qualification of new nuclear materials with superior irradiation resistance requires expensive irradiation exposure and post-irradiation examination before consideration into industrial nuclear structural components. The development of miniaturized test methods is needed for enhanced cost/time efficient testing, while enabling comparative and robust material property estimation in a timely and high throughput manner. The Small Punch Test (SPT) is drawing much interest, especially since the publication of an European standard. Motivated by this standard, a new SP test sample geometry is proposed in order to reduce the material volume to be tested, hences increasing the number of samples that can be introduced in an irradiation rig. The modified sample diameter has been reduced from 8 to 5.35 mm. The qualification of this new design is described here together with a detailed description of the SPT setup modification as compared to the reference setup of the EN standard. Finite element analyses and a series of experiments have been conducted using both standard and reduced size SP samples to demonstrate that the modified test gives estimates of the basic mechanical properties with the same magnitude of error and validates the modified sample geometry for usage in irradiated material testing.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155491"},"PeriodicalIF":2.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.jnucmat.2024.155492
Ioannis Alakiozidis , Callum Hunt , Albert D. Smith , Mia Maric , Zaheen Shah , Antoine Ambard , Philipp Frankel
Cold spray deposition has emerged as a promising method for applying protective coatings in the nuclear industry, particularly for enhancing the accident tolerance of fuel assemblies. In this process, helium gas is often used to propel solid powder particles towards the target substrate, however, nitrogen gas is also considered due to its significantly lower cost. In this study, we investigate the influence of nitrogen and helium gas as propellants on the properties and microstructure of pure chromium (Cr) coatings on zirconium (Zr) alloy cladding tubes. Employing Scanning Electron Microscopy (SEM) and electron and x-ray diffraction techniques (EBSD, XRD), we explore the structural characteristics of the coatings. Additionally, in-situ SEM tensile testing at room temperature, coupled with Digital Image Correlation (DIC), is utilized to assess the coating cracking behaviour. Our findings reveal distinct differences in coating morphology and residual stress between nitrogen and helium propelled Cr coatings. The nitrogen-propelled coating exhibits a more porous structure with smoother coating/substrate interfaces and lower compressive residual stress compared to the helium-propelled one. This results in earlier strain-induced crack initiation and higher crack density at lower strains (0.5–2%). However, at higher strains (2–5%), both coatings demonstrate identical crack saturation densities (saturated number of cracks per unit length), accompanied by similar crack toughening mechanisms and evidence of shear strain bands at intercrack regions, indicative of plasticity onset.
冷喷沉积已成为核工业应用保护涂层的一种很有前途的方法，特别是用于提高燃料组件的事故耐受性。在这一过程中，通常使用氦气将固体粉末颗粒推向目标基底，但由于氮气的成本明显较低，因此也考虑使用氮气。在本研究中，我们研究了氮气和氦气作为推进剂对锆（Zr）合金覆层管上纯铬（Cr）涂层的性能和微观结构的影响。我们采用扫描电子显微镜（SEM）以及电子和 X 射线衍射技术（EBSD、XRD）来探索涂层的结构特征。此外，我们还利用室温下的原位扫描电子显微镜拉伸测试和数字图像相关性（DIC）来评估涂层的开裂行为。我们的研究结果表明，氮气和氦气推进的铬涂层在涂层形态和残余应力方面存在明显差异。与氦气推进的涂层相比，氮气推进的涂层表现出更多孔的结构，涂层/基体界面更光滑，压缩残余应力更低。因此，在较低应变（0.5%-2%）时，应变诱发的裂纹萌发较早，裂纹密度较高。然而，在较高应变（2%-5%）下，两种涂层显示出相同的裂纹饱和密度（单位长度上的饱和裂纹数），并伴有类似的裂纹增韧机制和裂纹间区域的剪切应变带，表明塑性开始出现。
{"title":"Microstructure and mechanical performance of cold spray Cr coatings","authors":"Ioannis Alakiozidis , Callum Hunt , Albert D. Smith , Mia Maric , Zaheen Shah , Antoine Ambard , Philipp Frankel","doi":"10.1016/j.jnucmat.2024.155492","DOIUrl":"10.1016/j.jnucmat.2024.155492","url":null,"abstract":"<div><div>Cold spray deposition has emerged as a promising method for applying protective coatings in the nuclear industry, particularly for enhancing the accident tolerance of fuel assemblies. In this process, helium gas is often used to propel solid powder particles towards the target substrate, however, nitrogen gas is also considered due to its significantly lower cost. In this study, we investigate the influence of nitrogen and helium gas as propellants on the properties and microstructure of pure chromium (Cr) coatings on zirconium (Zr) alloy cladding tubes. Employing Scanning Electron Microscopy (SEM) and electron and x-ray diffraction techniques (EBSD, XRD), we explore the structural characteristics of the coatings. Additionally, <em>in-situ</em> SEM tensile testing at room temperature, coupled with Digital Image Correlation (DIC), is utilized to assess the coating cracking behaviour. Our findings reveal distinct differences in coating morphology and residual stress between nitrogen and helium propelled Cr coatings. The nitrogen-propelled coating exhibits a more porous structure with smoother coating/substrate interfaces and lower compressive residual stress compared to the helium-propelled one. This results in earlier strain-induced crack initiation and higher crack density at lower strains (0.5–2%). However, at higher strains (2–5%), both coatings demonstrate identical crack saturation densities (saturated number of cracks per unit length), accompanied by similar crack toughening mechanisms and evidence of shear strain bands at intercrack regions, indicative of plasticity onset.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155492"},"PeriodicalIF":2.8,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.jnucmat.2024.155490
Jiru Zhong , Mingtao Yang , Xinfu He , Kaishu Guan , Bintao Yu , Zhuangzhuang He
The small punch test (SPT) has been used extensively in nuclear industries to estimate mechanical properties changes of metals due to irradiation. This paper aims to propose more accurate approaches for SPT to estimate the yield and ultimate tensile strength of metals. The relationship between the SPT force and the yield and ultimate tensile strength of materials was studied by using finite element simulation data, and then three approaches were developed to determine tensile properties of materials by means of SPT. Force method and Slop method were developed to derive the ultimate tensile strength of metals from SPT curves, and Area method was proposed to determine the yield and ultimate tensile strength of metals. The accuracy of these approaches were verified by two candidate structural material for fusion reactors (CLF-1 steel and 9Cr-ODS steel) and other 10 structural materials. Area method gives more accurate evaluation on the yield strength of metals than the correlation method given in European standard on SPT. In addition, the developed approaches have advantages in estimating the tensile properties of low ductility metals.
{"title":"Improved approaches for small punch test to estimate the yield and ultimate tensile strength of metallic materials","authors":"Jiru Zhong , Mingtao Yang , Xinfu He , Kaishu Guan , Bintao Yu , Zhuangzhuang He","doi":"10.1016/j.jnucmat.2024.155490","DOIUrl":"10.1016/j.jnucmat.2024.155490","url":null,"abstract":"<div><div>The small punch test (SPT) has been used extensively in nuclear industries to estimate mechanical properties changes of metals due to irradiation. This paper aims to propose more accurate approaches for SPT to estimate the yield and ultimate tensile strength of metals. The relationship between the SPT force and the yield and ultimate tensile strength of materials was studied by using finite element simulation data, and then three approaches were developed to determine tensile properties of materials by means of SPT. Force method and Slop method were developed to derive the ultimate tensile strength of metals from SPT curves, and Area method was proposed to determine the yield and ultimate tensile strength of metals. The accuracy of these approaches were verified by two candidate structural material for fusion reactors (CLF-1 steel and 9Cr-ODS steel) and other 10 structural materials. Area method gives more accurate evaluation on the yield strength of metals than the correlation method given in European standard on SPT. In addition, the developed approaches have advantages in estimating the tensile properties of low ductility metals.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155490"},"PeriodicalIF":2.8,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.jnucmat.2024.155468
Zongyao Ge , Shengheng Tan , Yingju Li , Liangjin Bao , Xiaohui Feng , Tianyu Liu , Yuansheng Yang
{"title":"Corrigendum to “Thermal corrosion behavior of Inconel 693, Hastelloy N and 310S in ceramic waste forming reactions” [J. Nucl. Mater. 603(2025)155416]","authors":"Zongyao Ge , Shengheng Tan , Yingju Li , Liangjin Bao , Xiaohui Feng , Tianyu Liu , Yuansheng Yang","doi":"10.1016/j.jnucmat.2024.155468","DOIUrl":"10.1016/j.jnucmat.2024.155468","url":null,"abstract":"","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155468"},"PeriodicalIF":2.8,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142560921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.jnucmat.2024.155489
Qingsong Chen , Jun Yi , Qing Li , Xiong Jiang , Xifan Ding , Xi Zhou , Maolin Zhao , Chunhai Liu , Jijun Yang
The thick Cr coated Zr-4 alloys were prepared by magnetron sputtering deposition and their microstructure evolution and high-temperature air oxidation behaviour were investigated. Oxidation tests showed that the thick Cr coatings can improve the high-temperature air oxidation resistance of Zr-4 alloy even if the α-Zr(O) layer was formed at some regions. The mechanism of high-temperature air oxidation was also discussed in detail, and these experimental results could provide data for establishing a reliable prediction model of this degradation.
{"title":"Microstructure evolution and high temperature air oxidation behaviour of thick Cr coatings at 1200°C","authors":"Qingsong Chen , Jun Yi , Qing Li , Xiong Jiang , Xifan Ding , Xi Zhou , Maolin Zhao , Chunhai Liu , Jijun Yang","doi":"10.1016/j.jnucmat.2024.155489","DOIUrl":"10.1016/j.jnucmat.2024.155489","url":null,"abstract":"<div><div>The thick Cr coated Zr-4 alloys were prepared by magnetron sputtering deposition and their microstructure evolution and high-temperature air oxidation behaviour were investigated. Oxidation tests showed that the thick Cr coatings can improve the high-temperature air oxidation resistance of Zr-4 alloy even if the α-Zr(O) layer was formed at some regions. The mechanism of high-temperature air oxidation was also discussed in detail, and these experimental results could provide data for establishing a reliable prediction model of this degradation.</div></div>","PeriodicalId":373,"journal":{"name":"Journal of Nuclear Materials","volume":"604 ","pages":"Article 155489"},"PeriodicalIF":2.8,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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