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Green energy collection is crucial for achieving future net‐zero carbon emissions, with energy harvesting being a key solution. Silicon, a widely used p‐type semiconductor doped with boron ions, is prevalent in modern electronics. However, the impact of lattice boundaries from ion implantation doping on thermoelectric properties remains underexplored. A heavily boron‐doped silicon layer is used to enhance thermoelectric performance. The layers, formed on silicon, exhibit epitaxial crystal structures under all doping conditions using an ion implantation system. Transmission electron microscopy and atom probe tomography reveal that boron interstitial structures create boundaries in the silicon lattice. These boundaries effectively reduce the thermal conductivity of boron‐doped silicon compared to intrinsic silicon. At 372.76 K, the best power factor of the heavily boron‐doped silicon layer is 3.05 mW/m·K2, obtained at an implant dose of 1016 cm−2. This study demonstrates the raised electrical conductivity is induced by effectively substituting silicon with boron atoms, and the reduced thermal conductivity is caused by boron interstitial‐formed boundaries in silicon. These findings highlight the potential of heavily boron‐doped silicon in improving thermoelectric materials and advancing energy‐efficient technologies. [ABSTRACT FROM AUTHOR]

Changes in the structural state of steels of VVER-1000 reactor pressure vessels (RPVs) at an extended lifetime of 60 years and more were considered. A comprehensive analysis of available experimental data on changes in the structural state of RPV materials under irradiation was carried out. Extended dose dependences of the accumulation rate of radiation-induced structural elements and grain-boundary segregation of phosphorus are presented. The nature of changes in strength characteristics and critical brittleness temperature of RPV materials due to irradiation was shown. A preliminary estimate of the lifetime of RPV steels depending on their nickel content was made basing on the study of trends in the volume density and average size of radiation-induced structural elements, radiation defects, and radiation embrittlement mechanisms. [ABSTRACT FROM AUTHOR]

(MoTaTiVW)C x high entropy ceramics with varying carbon to metal ratio in the range of 0.75–0.97 were synthesized by by reactive spark plasma sintering. The effect of ball milling time on particle size, phase evolution and carbon pick-up due to toluene decomposition were studied. Formation of single-phase high entropy carbide having face-centered cubic (FCC) crystal structure was confirmed by X-ray diffraction (XRD), electron backscattered diffraction (EBSD) and Selected area diffraction pattern (SAED) analysis of the sintered compacts. Transmission Kikuchi Diffraction images revealed presence of equiaxed nature of the grains. Transmission electron microscopy images revealed the presence of an intergranular phase at grain boundaries and triple junctions. 3D-Atom Probe Tomography studies showed uniform distribution of elements within the grains with some segregation of impurity elements Fe and Co to the grain boundaries indicating minor contribution of liquid phase sintering to densification. The grain size of single-phase sintered compacts ranged between 1.69 ± 0.60 μm to 4.6 ± 1.0 μm. A low sintering temperature and higher milling time resulted in finer grain size The microhardness was found to increase with milling time and C/M ratio. The microhardness, Young's modulus and indentation fracture toughness lied between 2221 HV 0.1 to 2732 HV 0.1 , 370 GPa–473 GPa, 3.6 MPa m1/2 to 4.4 MPa m1/2, respectively. The highest microhardness and indentation fracture toughness was found to be 2732 ± 80 HV 0.1 and 4.4 MPa m1/2 on par with reported literature for other high entropy carbides. [ABSTRACT FROM AUTHOR]

In natural corundum, a strong geochemical correlation is sometimes observed between Be and heavy high field strength elements (HHFSEs) such as Nb, Ta and W, and it has been hypothesized that trace elements are hosted in primary inclusions. However, no known mineral enriched in both Be and HHFSEs stable at these geological conditions can explain this correlation. To understand how Be and HHFSEs are distributed in natural corundum down to the atomic scale, two natural Be-bearing sapphire crystals from Afghanistan and Nigeria are studied using laser ablation inductively coupled plasma and time-of-flights secondary ion mass spectrometry, atom probe tomography and transmission electron microscopy. In addition to common trace elements such as Mg, Ti, and Fe, Be and W are detected in the metamorphic sapphire from Afghanistan, whereas Be, Nb and Ta are detected in the magmatic sapphire from Nigeria. Nanoclustering in both samples shows fractionation of Be and high field strength elements (including Ti) by atomic mass, suggesting a secondary process controlled by solid-state diffusion. The homogeneously distributed W and the secondary nano-precipitates bearing Nb and Ta indicates that HHFSEs can be incorporated into the corundum structure during crystallization, most likely through preferred adsorption on the growth surface. The strong correlation between Be and HHFSEs across the growth zones is probably due to Be being attracted by HHFSEs to partially balance the charge when incorporated into the corundum structure. The enrichment of high field strength elements by growth kinetics may result in supersaturated concentrations during crystallization, allowing them to precipitate out when the host corundum is heated above its formation temperature by basaltic magma. Comparison with previous transmission electron microscope studies suggests the same process for incorporating Be and HHFSEs also applies to other natural corundums from different localities. [ABSTRACT FROM AUTHOR]

Precipitation of the secondary phase is a key factor that influences the strengthening effect of nickel-based superalloy. The precipitation behaviours of the M23C6 carbide and γ′-Ni3(Ti, Al) phase in Inconel 617B alloy aged at 700°C for different times were studied by scanning electron microscopy, transmission electron microscopy and atom probe tomography. Plate-like carbide nucleated in the interior of grain and irregular shape carbide precipitated at grain boundary respectively during the early stage of ageing. γ′ particle co-precipitated around carbide is a common microstructure feature during ageing for 5–160 h. After ageing for 160 h, γ′ phase is the main secondary phase. The carbide only distributes on the grain boundary, high density γ′ particle homogeneously distributes in the matrix after a longer ageing time. Elemental partitioning to the secondary phases and composition profiles across different phases was quantitatively analysed. Enrichments of Ti and Al at the carbide/γ interface are directly observed, which act as the nucleation site of γ′ particles during ageing. Enrichments of B, Si and Co at different interfaces are also detected. Based on the experimental results, the precipitation mechanisms of γ′ particles and carbide were discussed. [ABSTRACT FROM AUTHOR]

The design of a Cd‐free and wider‐bandgap buffer layer is stringent for future Cu(In,Ga)Se2 (CIGSe) thin‐film solar cell applications. For that, an In2S3 buffer layer alloyed with a limited amount of O (well below 25 mol%) has been proposed as a pertinent alternative solution to CdS or Zn(O,S) buffers. However, the chemical stability of the In2S3/CIGSe heterointerface when O is added is not completely clear. Therefore, in this work, the buffer/absorber interface for a series of sputter‐deposited In2S3 buffers with and without O is investigated. It is found that the solar cell with the highest open‐circuit voltage is obtained for the O‐free In2S3 buffer sputtered at 220 °C. This improved open‐circuit voltage could be explained by the presence of a 20 nm‐thick ordered vacancy compound (OVC) at the absorber surface. A much thinner OVC layer (5 nm) or even the absence of this layer is found for the cell with In2(O0.25S0.75)3 buffer layer where O is inserted. The volume fraction of the OVC layer is directly linked with the magnitude of Cu diffusion from the CIGSe surface into the In2(OxS1−x)3 buffer layer. The O addition strongly reduces the Cu diffusion inside the buffer layer up to complete suppression for very high O contents in the buffer. Finally, it is discussed that the presence of the OVC layer may lower the valence band maximum, thereby forming a hole barrier, suppressing charge carrier recombination at the In2(OxS1−x)3/CIGSe interface, which could result in an increased open‐circuit voltage. [ABSTRACT FROM AUTHOR]

Main‐group chalcogenides show outstanding performance for phase‐change data storage and thermoelectric energy conversion applications. A common denominator for these different property requirements is ascribed to the metavalent bonding (MVB) mechanism. Atom probe tomography (APT) provides a unique way to distinguish MVB from other bonding mechanisms by determining the bond‐breaking behavior. Specifically, an unusually high probability to dislodge several fragments upon one successful laser pulse (probability of multiple events [PME]) is found in metavalently bonded crystalline phase‐change and thermoelectric materials. In contrast, amorphous phase‐change materials and poor thermoelectrics usually show lower PME values. This indicates that the large optical and electrical contrast between the crystalline and amorphous chalcogenides is attributed to a transition of chemical bonding. A strong correlation between high thermoelectric performance and large PME is also established. Besides, APT can investigate structural defects on the subnanometer scale. These characteristics reveal the interdiffusion of elements in interfacial phase‐change materials and revisit its switching mechanism. The complex role of structural defects such as grain boundaries in tuning the thermoelectric properties can also be unraveled by investigating the local composition and bonding mechanism at defects. This review demonstrates that APT is a powerful technique for designing phase‐change and thermoelectric materials. [ABSTRACT FROM AUTHOR]

Understanding crystal characteristics down to the atomistic level increasingly emerges as a crucial insight for creating solid state platforms for qubits with reproducible and homogeneous properties. Here, isotope concentration depth profiles in a SiGe/28Si/SiGe heterostructure are analyzed with atom probe tomography (APT) and time‐of‐flight secondary‐ion mass spectrometry down to their respective limits of isotope concentrations and depth resolution. Spin‐echo dephasing times T2echo=128μs$T_2^\mathbf {echo}=128 \,\umu\mathrm{s}$ and valley energy splittings EVS around 200μeV$200 \,\umu\mathrm{e\mathrm{V}}$ have been observed for single spin qubits in this quantum well (QW) heterostructure, pointing toward the suppression of qubit decoherence through hyperfine interaction with crystal host nuclear spins or via scattering between valley states. The concentration of nuclear spin‐carrying 29Si is 50 ± 20ppm in the 28Si QW. The resolution limits of APT allow to uncover that both the SiGe/28Si and the 28Si/SiGe interfaces of the QW are shaped by epitaxial growth front segregation signatures on a few monolayer scale. A subsequent thermal treatment, representative of the thermal budget experienced by the heterostructure during qubit device processing, broadens the top SiGe/28Si QW interface by about two monolayers, while the width of the bottom 28Si/SiGe interface remains unchanged. Using a tight‐binding model including SiGe alloy disorder, these experimental results suggest that the combination of the slightly thermally broadened top interface and of a minimal Ge concentration of 0.3$0.3$% in the QW, resulting from segregation, is instrumental for the observed large EVS=200μeV$E_\mathrm{VS}=200 \,\umu\mathrm{e\mathrm{V}}$. Minimal Ge additions <1%, which get more likely in thin QWs, will hence support high EVS without compromising coherence times. At the same time, taking thermal treatments during device processing as well as the occurrence of crystal growth characteristics into account seems important for the design of reproducible qubit properties. [ABSTRACT FROM AUTHOR]

In the quest for lightweight high‐performance metallic materials in transportation, the limitations of high‐strength Al‐based alloys in high‐temperature (HT) applications have posed a significant challenge. To overcome this long‐standing bottleneck, an innovative design strategy, combining entropy‐driven compositional design and rapid solidification processing, to develop "Al‐based superalloys" with a γ/γ′ duplex microstructure reminiscent of Ni‐based superalloys is presented. By incorporating multirefractory elements (Ti, Zr, Hf, Nb, and Ta) into the alloy design, a high‐volume fraction of thermally stable coherent γ′ phase for strengthening the Al‐rich face‐centered cubic matrix from room temperature (RT) to temperatures close to the melting point is achieved. The developed Al‐based superalloys exhibit exceptional specific yield strength and specific Young's modulus, surpassing aerospace aluminum, cobalt, nickel, and titanium alloys from RT to HT. Moreover, our ultra‐strong alloys demonstrate deformability and exhibit fine‐dimpled fracture behavior. The versatility of our fundamental research on Al‐based superalloys demonstrates their potential and can inspire further research in this field. This work opens new possibilities for the development of next‐generation lightweight alloys with novel microstructures and outstanding mechanical properties. [ABSTRACT FROM AUTHOR]

[Objective] Atom probe tomography (APT) is an effective technique that can provide spatial and compositional information on atoms at the nanoscale with exceptional resolution. It reconstructs three-dimensional spatial distribution maps of atoms, allowing for a detailed quantitative analysis of a material's internal microstructure and nanostructure. However, due to the varying field evaporation voltages or ionization field strengths of different elements, some atoms, particularly those in second-phase precipitates, may exhibit positional lag in the reconstructions, leading to a "local magnification effect." This effect can distort the apparent morphology of the precipitates. In addition, flying ions composed of multiple elements may have mass-to-charge ratios that overlap with single atomic ions in the mass spectrum, causing compositional deviations. The sample temperature and pulse fraction during APT analysis can significantly impact spatial and compositional resolution, potentially leading to inaccuracies in the final data. This study investigates the influence of these parameters on the alloy matrix composition, with a particular focus on second-phase components susceptible to local magnification effects, aiming to identify the key factors affecting mass spectrum noise and compositional accuracy, thereby enhancing the reliability of APT reconstruction data. [Methods] In this study, a precipitation-strengthened 7085 aluminum alloy was selected, and needle-shaped specimens with a curvature radius of less than 100 nm were prepared using standard two-step electropolishing. A LEAP 4000HR atomic probe was employed for analysis. The maximum separation algorithm was used to identify clusters or second-phase particles, with Mg, Si, and Cu selected as clustering solutes, requiring a minimum of 10 atoms. The cluster analysis parameters included a separation distance of 0.7 nm and an envelope distance of 0.5 nm. Two sets of parameters were tested: (1) a fixed pulse fraction of 15% while varying the sample temperature, and (2) a fixed sample temperature of 20 K while varying the pulse fraction. The detection rate was maintained at 1%, and the pulse frequency was set at 200 kHz to study the effects of sample temperature and pulse fraction on background noise, chemical composition, and second-phase distribution characteristics in the mass spectrum. [Results] The experimental results revealed the presence of two precipitated phases within the aluminum alloy: small MgZn2 particles and larger Al3(Sc,Zr) particles. As the sample temperature increased, the background noise intensity in the mass spectrum consistently increased, while the concentrations of Zn, Mg, Cu, and Si remained largely unchanged. However, the Zr content increased significantly and continuously with increasing temperature. The size of the MgZn2 precipitates remained almost constant, although their number density initially decreased before increasing again. In contrast, as the pulse fraction increased, the background noise intensity decreased and stabilized at values ≥25%. The concentrations of the primary alloying elements remained stable, but the Zr content decreased steadily, with no significant changes observed in the second-phase precipitation characteristics. [Conclusions] For optimal APT analysis of 7085 aluminum alloy, a sample temperature around 20 K and a pulse fraction between 15% and 20% are recommended. These conditions minimize background noise intensity and improve the accuracy of chemical composition measurements and second-phase distribution characteristics, thereby enhancing the overall reliability of the APT data. [ABSTRACT FROM AUTHOR]

This investigation presents the development of third-generation advanced high-strength steels (AHSS) for automotive industries, focusing on materials with higher strength, plasticity, and crashworthiness. Three alloy steels Fe-6Mn-(1, 1.6, 2.0) Si were developed via a melting route using an arc melting furnace followed by homogenization at 1200 °C, hot rolling at 1100 °C, and then air cooling. The developed steels are characterized using FE-SEM, XRD, microhardness tester, and universal testing machine. The FE-SEM micrographs exhibit a complex phase microstructure containing pearlite, retained austenite, martensite, ferrite, and bainite. The microhardness values of novel alloys are measured as 423, 441, and 475 VHN. The tensile strengths of alloys were achieved at 1409 MPa, 1497 MPa, and 1438 MPa with elongations of 18, 15, and 14% respectively. Atom probe tomography results confirmed the presence of retained austenite of film thickness 25–27 nm. The fracture surface of alloy steel containing 1 wt% Si and 6 wt% Mn exhibits dimples, causing ductile fracture, while alloy steel containing 1.6–2.0 wt% Si and 6 wt% Mn combines dimples and facets, confirming intergranular fracture with a 14 % ductility limit. The average dimple size decreases from 0.82 µm to 0.64 µm with an increase in silicon from 1 wt% to 2 wt%. [ABSTRACT FROM AUTHOR]

The weld cladding on the inner surface of nuclear pressure vessels due to irradiation damage and thermal effect presents to a safety issue. Unfortunately, the effect of irradiation and long-term thermal treatment on the austenitic microstructure and austenitic hardening in austenitic stainless steel weld metals (ASSWMs) remains poorly understood. In this study, the effects of irradiation and thermal treatment on the austenitic microstructures and austenitic hardening of 308L ASSWMs were investigated using nanoindentation, atom probe tomography and transmission electron microscopy. The results suggested that irradiation resulted in the formation of Ni/Si-rich clusters, voids, and Frank loops in austenite, thereby inducing austenitic hardening. Subsequently, thermal treatment decreased the size and the number of Frank loops in irradiated austenite, which had a minor effect on austenitic hardening. However, thermal treatment promoted the growth of Ni/Si-rich clusters and void formation, which have a primary effect on austenitic hardening, thereby enhancing the hardening of irradiated austenite. Furthermore, thermal treatment has little effect on the microstructure and hardening of austenite. Then, irradiation promoted the formation of Ni/Si-rich clusters, voids, and Frank loops in thermally treated austenite, resulting in austenitic hardening. The interaction of irradiation and thermal treatment can promote the formation of voids. The austenitic hardening was mainly due to the contribution of Frank loops, voids, and Ni/Si-rich clusters, which acted as short-range barriers by pin-moving dislocations.

Pressureless sintering processing was adopted to fabricate transparent aluminum oxynitride (AlON) ceramics by using magnesium oxide (MgO) as a sintering additive into synthetic single phased aluminum oxynitride powder. Under the condition of adding 0.6 wt% magnesium oxide, the relative density of aluminum oxynitride ceramics increased from 98.67% with no addition to 99.9% after being held at 1800°C for 24 h, coupled by a reducing of average grain size from 190 µm to 130 µm. The optical linear transmittance of the AlON ceramic sample (thickness 1.2 mm) reached 84.2% at the wavelength of 1100 nm. The microstructural characterizations by energy dispersive spectroscopy and atom probe tomography indicated that the doping Mg element was uniformly dispersed inside aluminum oxynitride grains of as‐sintered ceramics. It was demonstrated that magnesium oxide played a key role in inhibiting the movement of grain boundaries, eliminating pores, leading to the fully densification of aluminum oxynitride ceramics. [ABSTRACT FROM AUTHOR]

An atomic‐scale understanding of how electrocatalyst surfaces reconstruct and transform during electrocatalytic reactions is essential for optimizing their activity and longevity. This is particularly important for the oxygen evolution reaction (OER), where dynamic and substantial structural and compositional changes occur during the reaction. Herein, a multimodal method is developed by combining X‐ray fine structure absorption and photoemission spectroscopy, transmission electron microscopy, and atom probe tomography with electrochemical measurements to interrogate the temporal evolution of oxidation states, atom coordination, structure, and composition on Co2MnO4 and CoMn2O4 cubic spinel nanoparticle surfaces upon OER cycling in alkaline media. Co2MnO4 is activated at the onset of OER due to the formation of ≈2 nm Co‐Mn oxyhydroxides with an optimal Co/Mn ratio of ≈3. As OER proceeds, Mn dissolution and redeposition occur for the CoMn oxyhydroxides, extending the OER stability of Co2MnO4. Such dynamic dissolution and redeposition are also observed for CoMn2O4, leading to the formation of less OER‐active Mn‐rich oxides on the nanoparticle surfaces. This study provides mechanistic insights into how dynamic surface reconstruction and transformation affect the activity and stability of mixed CoMn cubic spinels toward OER. [ABSTRACT FROM AUTHOR]

Dopant‐induced microstructure in thermoelectric materials significantly affects thermoelectric properties and offers a potential to break the interdependence between electron and phonon transport properties. However, identifying all‐scale dopant‐induced microstructures and correlating them with thermoelectric properties remain a huge challenge owing to a lack of detailed microstructural characterization encompassing all length scales. Here, the hierarchical boron (B)‐induced microstructures in B‐doped Si80Ge20 alloys with different B concentrations are investigated to determine their precise effects on thermoelectric properties. By adopting a multi‐scale characterization approach, including X‐ray diffraction, scanning and transmission electron microscopy, and atom probe tomography, five distinctive B‐induced phases within Si80Ge20 alloys are identified. These phases exhibit different sizes, compositions, and crystal structures. Furthermore, their configuration is comprehensively determined according to B doping concentrations to elucidate their consequential impact on the unusual changes in carrier concentration, density‐of‐states effective mass, and lattice thermal conductivity. The study provides insights into the intricate relationship between hierarchical dopant‐induced microstructures and thermoelectric properties and highlights the importance of investigating all‐scale microstructures in excessively‐doped systems for determining the precise structure‐property relationships. [ABSTRACT FROM AUTHOR]

Herein, the influence of one‐ and two‐step preageing treatments prior to the artificial ageing step to peak age condition for three different 6xxx alloys, from low to high alloy content, is investigated. Analysis of the preaged conditions using atom probe tomography (APT) reveals a broad distribution of Mg and Si clusters, with some instances of Guinier‐Preston I zones present. Additionally, the high alloyed system exhibits a growth of precipitates toward a needle‐like shaped. These clusters formed during the preageing treatment serve as nucleation sites in the subsequent artificial ageing treatment, leading to an increase in hardness. Microstructural analysis conducted using transmission electron microscopy and APT demonstrates a reduction in the average precipitate length and a more narrow size distribution for T6 condition. This indicates that the preageing treatment results in a decreased portion of already overaged precipitates compared to the direct aged condition. Consequently, the more narrow size distribution of the precipitates leads to more effective hardening of the material, as a higher portion of precipitates is at or close to their optimum size. The investigations highlight the significant influence and positive effect of a preageing treatment at lower temperatures on the subsequent artificial ageing treatment. [ABSTRACT FROM AUTHOR]

Mechanisms relating to growth and/or compositional modification of zircon occur at the atomic scale. For felsic igneous systems, processes responsible for growth patterns in zircon have previously remained elusive as the volume of material needed to analyze these compositional features using traditional in-situ methods is considerably larger than the typical sub-micron scale distribution of trace elements. To illuminate some of these driving forces, we characterize and quantify minor and trace element concentrations in igneous zircon grains by combining methods of cathodoluminescence (CL) imaging, electron microprobe microanalysis (EMPA) elemental maps for Hf, Y, Yb and U or Th, and atom probe tomography (APT). We focus on igneous zircon from the Chon Aike Silicic Large Igneous Province (Patagonia) that provide novel insights into (1) dissolution and re-crystallization during crustal anatexis, (2) crystallization to produce oscillatory zonation patterns that are typical of igneous zircons, and (3) the incorporation of trace element impurities (e.g., P, Be, and Al) at the nanoscale. Significantly, these APT volumes provide nanoscale sampling of boundaries between oscillatory growth zones in an igneous zircon to reveal compositional zoning of Y and, to a lesser extent P, which appear as high-angle, planar features. These concentration boundaries measured on the order of 10 to 12 nm are difficult to reconcile with proposed mechanisms for generating fine-scaled oscillations. Lastly, we fit diffusional profiles to measured Y concentrations to provide an estimate on the maximum timescales of zircon growth prior to eruption, as a function of the temperature at which diffusion occurred. When combined with known pressure-temperature-time paths for the magmatic system considered, these extremely short diffusion profiles that are resolvable by APT provide a powerful method to constrain timescales of crystal growth. [ABSTRACT FROM AUTHOR]

Accessory minerals like zircon, rutile and monazite are routinely studied to inform about the timing and nature of geological processes. These studies are underpinned by our understanding of the transfer processes of trace elements and the assumption that the isotopic systems remain undisturbed. However, the presence of microstructures or Pb-bearing phases in minerals can lead to the alteration of the Pb isotopic composition. To gain insight into the relationship between Pb isotopic alterations from inclusions and microstructures, this study focused on inclusions from an ultra-high-temperature metamorphic rutile. The studied inclusions are submicrometer monazites, a common mineral rich in Pb but normally not present in rutile. The sample is sourced from Mt. Hardy, Napier Complex, East Antarctica, an ultra-high-temperature (UHT) metamorphic terrane. By applying correlative analytical techniques, including electron backscatter diffraction mapping, transmission electron microscopy (TEM), and atom probe tomography, it is shown that monazite inclusions are often in contact with low-angle boundaries and yield no preferred orientation. TEM analysis shows the monazite core has a mottled texture due to the presence of radiation damage and nanoclusters associated with the radiation damage defects that are rich in U, Pb, and Ca. Some monazites exhibit a core-rim structure. The rim yields clusters composed of Ca- and Li-phosphate that enclose Pb nanoclusters that are only present in small amounts compared to the core, with Pb likely diffused into the rutile-monazite interface. These textures are the result of two stages of Pb mobility. Initial Pb segregation was driven by volume diffusion during UHT metamorphism (2500 Ma). The second stage is a stress-induced recrystallization during exhumation, leading to recrystallization of the monazite rim and trace element transport. The isotopic signature of Pb trapped within the rutile-monazite interface constrains the timing of Pb mobility to ca. 550 Ma. [ABSTRACT FROM AUTHOR]

The reactor pressure vessel (RPV) is a critical barrier in nuclear power plants, but its embrittlement during service poses a significant safety challenge. This study investigated the effects of Cu-enriched clusters on the mechanical and magnetic properties of Fe-0.9 wt.%Cu model alloys through thermal aging. Using Vickers hardness tests, Magnetic Barkhausen Noise (MBN) detection, and Atom Probe Tomography (APT), the study aimed to establish a quantitative correlation between MBN signals, Vickers hardness, and Cu-enriched clusters, facilitating the non-destructive testing of RPV embrittlement. Experimental results showed that the hardness and MBN parameters (RMS and Vpp values) changed significantly with aging time. The hardness increased rapidly in the early stage (under-aged), followed by a plateau and then a decreasing trend (over-aged). In contrast, MBN parameters decreased initially and then increased. APT analysis revealed that Cu-enriched clusters increase in size to 4.60 nm and coalesced during aging, with their number density peaking to 3.76 × 1023 m−3 before declining. An inverse linear correlation was found between MBN signals and the combined factor Nd2Rg (product of the number density squared and the mean radius of Cu-enriched clusters). This correlation was consistent across both under-aged and over-aged states, suggesting that MBN signals can serve as applicable indicators for the non-destructive evaluation of RPV steel embrittlement. [ABSTRACT FROM AUTHOR]

To detect hydrogen in materials at the atomic scale, atom probe tomography is now regularly used. In order to avoid cumbersome cryo‐preparation to suppress diffusion, often hydrogen is charged only into the finished specimen. Here, the use of hydrogen gas over electrochemical hydrogen has the advantage that the specimen is not contaminated with an electrolyte. So far, this "charging" has been done in large, expensive systems. Here, we introduce small devices that enable the exposure of atom probe specimens to hydrogen and potentially other gases, using only very small gas volumes. This enables the operation in regular laboratory environments without additional safety measures. These devices can be used to expose the specimen to hydrogen up to 10 bar/90°C. Higher temperatures may be attained with small changes. Validation of the success of charging with these setups is demonstrated through experiments employing deuterium charging of palladium atom probe tips. Research Highlights: Enabling the exposure of atom probe specimens to hydrogen and potentially other gases, using only very small gas volumes.Built setups can be assembled with little money and from freely available parts, making specimen charging much easier.Validation of the success of charging with these setups is demonstrated through experiments employing deuterium charging of palladium atom probe tips. [ABSTRACT FROM AUTHOR]

Herein, the potential of using the thermomechanical treatment ausforming to optimize the microstructure of PH 13‐8 Mo maraging steels is investigated. Of particular interest are the effects on the formation of β‐NiAl precipitates and reverted austenite during subsequent aging. Ausforming experiments at deformation temperatures of 400 and 600 °C and strains of 40% and 70% are conducted using a deformation dilatometer. Afterward, the samples are subjected to aging at temperatures varying from 482 to 593 °C. This is followed by a thorough microstructural characterization ranging from light optical microscopy to X‐Ray diffraction and atom probe tomography. The results demonstrate that ausforming effectively refines the microstructure, resulting in a significant increase in hardness. Moreover, it is revealed that the ausforming parameters have a noticeable influence on the number density of β‐NiAl precipitates and the amount of reverted austenite. A well‐balanced microstructure containing relatively fine precipitates and a high amount of reverted austenite can be achieved by ausforming at 600 °C with 40% strain. Overall, the results prove a promising potential of ausforming for PH 13‐8 Mo maraging steels with regard to tailoring optimized microstructures, which could ultimately benefit the aerospace industry where these alloys are used. [ABSTRACT FROM AUTHOR]

Abstract (AlxGa1–x)2O3 is an ultrawide‐bandgap semiconductor with a high critical electric field for next‐generation high‐power transistors and deep‐ultraviolet photodetectors. While (010)‐(AlxGa1–x)2O3 films have been studied, the recent availability of (100), (2¯01)‐Ga2O3 substrates have developed interest in (100), (2¯01)‐(AlxGa1–x)2O3 films. In this work, an investigation of microscopic and spectroscopic characteristics of (100), (2¯01), (010)–(AlxGa1–x)2O3 films is conducted. A combination of scanning transmission electron microscopy, atom probe tomography (APT), and first‐principle calculations (DFT) is performed. The findings reveal consistent in‐plane chemical homogeneity in lower aluminum content (x = 0.2) films. However, higher aluminum content (x = 0.5), showed inhomogeneity in (100), (010)–(AlxGa1–x)2O3 films attributed to their spectroscopic properties. The study expanded APT's capabilities to determine Ga─O and Al─O bond lengths by mapping their ion‐pair separations in detector space. The change in ion‐pair separations is consistent with varying orientations, irrespective of aluminum content. DFT also demonstrated a similar trend, concluding that Ga─O and Al─O bonding energy has an inverse relationship with their bond length as crystallographic orientations vary. This systematic study of growth orientation dependence of (AlxGa1–x)2O3 films’ microscopic and spectroscopic properties will guide the development of new (100) and (2¯01)‐(AlxGa1–x)2O3 along with existing (010)–(AlxGa1–x)2O3 films.

Abstract Green energy collection is crucial for achieving future net‐zero carbon emissions, with energy harvesting being a key solution. Silicon, a widely used p‐type semiconductor doped with boron ions, is prevalent in modern electronics. However, the impact of lattice boundaries from ion implantation doping on thermoelectric properties remains underexplored. A heavily boron‐doped silicon layer is used to enhance thermoelectric performance. The layers, formed on silicon, exhibit epitaxial crystal structures under all doping conditions using an ion implantation system. Transmission electron microscopy and atom probe tomography reveal that boron interstitial structures create boundaries in the silicon lattice. These boundaries effectively reduce the thermal conductivity of boron‐doped silicon compared to intrinsic silicon. At 372.76 K, the best power factor of the heavily boron‐doped silicon layer is 3.05 mW/m·K2, obtained at an implant dose of 1016 cm−2. This study demonstrates the raised electrical conductivity is induced by effectively substituting silicon with boron atoms, and the reduced thermal conductivity is caused by boron interstitial‐formed boundaries in silicon. These findings highlight the potential of heavily boron‐doped silicon in improving thermoelectric materials and advancing energy‐efficient technologies.