On the atomic nature of complex dislocation locks in C15 Laves phases Gang Liu, Sang-Hyeok Lee, Christian H. Liebscher, Siyuan Zhang, Xuyang Zhou, Jung Soo Lee, Shaolou Wei, Miquel Vega-Paredes, Peter Schweizer, Sandra Korte-Kerzel, Gerhard Dehm, Zhuocheng Xie, Frank Stein Acta Materialia, 2026 The practical applications of Laves alloys are hindered by their intrinsic brittleness at ambient temperature. Dislocation lock structures are expected to play a critical role in governing the plasticity of these alloys; however, their atomic-scale nature remains poorly understood. Here, combining conventional transmission electron microscopy analyses, atomic-resolution scanning transmission electron microscopy images, and atomistic simulations, we unveiled the types, configurations, and formation mechanisms of dislocation locks in a Nb-rich (35 at.% Nb) C15 NbCr 2 Laves phase alloy. Moreover, complex defect structures within the cores of dislocation locks, including antisite-like columns of Nb and vacancy-like columns of Cr, were experimentally identified at the atomic scale and rationalized by atomistic simulations. The dislocation locks may serve as preferential sites for crack initiation due to the localized stress concentration. Such stress concentration–induced cracking was experimentally confirmed by the observed intersection of slip planes. Furthermore, the formation mechanisms of four types of dislocation locks and their potentially distinct influences on crack initiation were discussed. The discovery of these lock structures and their influence on crack formation may offer new insights into defect engineering in Laves phases, paving the way for improved strategies to mitigate their intrinsic brittleness.
Complexions at the iron-magnetite interface Xuyang Zhou, Baptiste Bienvenu, Yuxiang Wu, Alisson Kwiatkowski da Silva, Colin Ophus, Dierk Raabe Nature Communications, 2025 Synthesizing distinct phases and controlling crystalline defects are key concepts in materials design. These approaches are often decoupled, with the former grounded in equilibrium thermodynamics and the latter in nonequilibrium kinetics. By unifying them through defect phase diagrams, we can apply phase equilibrium models to thermodynamically evaluate defects—including dislocations, grain boundaries, and phase boundaries—establishing a theoretical framework linking material imperfections to properties. Using scanning transmission electron microscopy (STEM) with differential phase contrast (DPC) imaging, we achieve the simultaneous imaging of heavy Fe and light O atoms, precisely mapping the atomic structure and chemical composition at the iron-magnetite (Fe/Fe3O4) interface. We identify a well-ordered two-layer interface-stabilized phase state (referred to as complexion) at the Fe[001]/Fe3O4[001] interface. Using density-functional theory (DFT), we explain the observed complexion and map out various interface-stabilized phases as a function of the O chemical potential. The formation of complexions increases interface adhesion by 20% and alters charge transfer between adjacent materials, impacting transport properties. Our findings highlight the potential of tunable defect-stabilized phase states as a degree of freedom in materials design, enabling optimized corrosion protection, catalysis, and redox-driven phase transitions, with applications in materials sustainability, efficient energy conversion, and green steel production.
Boron triggers grain boundary structural transformation in steel Xuyang Zhou, Sourabh Kumar, Siyuan Zhang, Xinren Chen, Baptiste Gault, et al. Nature Communications, 2025 Boron enhances the hardenability of low-alloyed steel and reduces embrittlement at low temperatures, at parts-per-million concentration levels. Its effectiveness arises from segregation to grain boundaries (GBs)-planar defects between crystals-yet atomic-scale evidence remains limited. We addressed this gap by synthesizing GBs with controllable geometry and orientation, enabling reproducible comparison with and without boron segregation. Differential phase-contrast imaging directly reveals boron at iron GBs, and in-situ TEM heating (20 °C to 800 °C) allows us to track the dynamic evolution of GB structures. We found that boron segregation induces local structural changes and triggers GB phase transformations, as corroborated by calculated GB defect phase diagrams spanning broad ranges of carbon and boron content. Our findings not only bridge a gap in understanding the interplay between GB structure and chemistry but also lay the groundwork for targeted design and passivation strategies in steel, potentially transforming its resistance to hydrogen embrittlement, corrosion, and mechanical failure.
Secondary grain boundary dislocations alter segregation energy spectra Xinren Chen, William Gonçalves, Yi Hu, Yipeng Gao, Patrick Harrison, Gerhard Dehm, Baptiste Gault, Wolfgang Ludwig, Edgar Rauch, Xuyang Zhou, Dierk Raabe Nature Communications, 2025 Grain boundaries (GBs) trigger structure-specific chemical segregation of solute atoms. According to the three-dimensional (3D) topology of grains, GBs - although defined as two-dimensional defects - cannot practically be free of curvature. This leads to discrete variations in the GB plane orientations. Topologically required arrays of secondary GB dislocations accommodate these variations as well as deviations from ideal coincidence site lattice GBs. We report here that these pattern-forming secondary GB dislocations can have an additional and, in some cases, even a much stronger effect on GB segregation than defect-free GBs. Using nanoscale correlative tomography combining crystallography and chemical analysis, we quantified the relationship between secondary GB dislocations and their segregation energy spectra for a model Fe-W alloy. This discovery unlocks design opportunities for advanced materials, leveraging the additional degrees of freedom provided by topologically-necessary secondary GB dislocations to modulate segregation.
APT Calibrator: A Multifunctional C# Software Application for Reconstruction Calibration in Atom Probe Tomography Xinren Chen, Yue Li, Eric Woods, Xuyang Zhou, Baptiste Gault Microscopy and Microanalysis, 2025 Atom probe tomography provides compositional mapping of materials at the nanoscale, and in that sense accurate reconstruction of the atomic positions is crucial for precise and accurate analysis. Here, we introduce the “APT Calibrator,” developed in C#, a software tool that aids in the calibration of atom probe tomography reconstructions. It integrates essential calibration methods proposed over the past two decades to derive the key hyperparameters, such as the image compression factor and field reduction factor, allows for dynamic reconstruction of the data using a newly introduced method based on the use of fiducial markers that we refer to as “golden seed,” and facilitates atom probe crystallographic analysis of microstructural defects. The software features a straightforward interface, simplifying the calibration process and making it more accessible.
Correlating Grain Boundary Character and Composition in 3-Dimensions Using 4D-Scanning Precession Electron Diffraction and Atom Probe Tomography Saurabh M. Das, Patrick Harrison, Srikakulapu Kiranbabu, Xuyang Zhou, Wolfgang Ludwig, Edgar F. Rauch, Michael Herbig, Christian H. Liebscher Small Methods, 2025 Grain boundaries (GBs) are dominant imperfections in nanocrystalline materials that form a complex 3D network. Solute segregation to GBs is strongly coupled to the GB character, which governs the stability and macroscopic properties of nanostructured materials. Here, a 3D transmission electron microscopy and atom probe tomography (APT) correlation framework are developed to retrieve the GB character and composition at the highest spatial resolution and chemical sensitivity by correlating 4D scanning precession electron diffraction tomography (4D‐SPEDT) and APT on the same sample. The 3D GB habit plane network and explore the preferential segregation of Cu and Si in a nanocrystalline Ni‐W alloy is obtained. The correlation of structural and compositional information reveals that Cu segregates predominantly along high‐angle GBs and incoherent twin boundaries, whereas Si segregation to low‐angle and incommensurate GBs is observed. The novel full 3D correlative approach employed in this work opens up new possibilities to explore the 3D crystallographic and compositional nature of nanomaterials. This lays the foundation for both probing the true 3D structure‐chemistry at the sub‐nanometer scale and, consequentially, tailoring the macroscopic properties of advanced nanomaterials.
Materials Design by Constructing Phase Diagrams for Defects Xuyang Zhou, Prince Mathews, Benjamin Berkels, Wassilios Delis, Saba Saood, Amel Shamseldeen Ali Alhassan, Philipp Keuter, Jochen M. Schneider, Sandra Korte‐Kerzel, Stefanie Sandlöbes‐Haut, Dierk Raabe, Jörg Neugebauer, Gerhard Dehm, Tilmann Hickel, Christina Scheu, Siyuan Zhang Advanced Materials, 2025 Phase transformations and crystallographic defects are two essential tools to drive innovations in materials. Bulk materials design via tuning chemical compositions is systematized using phase diagrams. It is shown here that the same thermodynamic concept can be applied to manipulate the chemistry at defects. Grain boundaries in Mg–Ga system are chosen as a model system, because Ga segregates to the boundaries, while simultaneously improving the strength and ductility of Mg alloys. To reveal the role of grain boundaries, correlated atomic‐scale characterization and simulation to scope and build phase diagrams for defects are presented. The discovery is enabled by triggering phase transformations of individual grain boundaries through local alloying, and sequentially imaging the structural and chemical changes using atomic‐resolution scanning transmission electron microscopy. Ab initio simulations determined the thermodynamic stability of grain boundary phases, and found out that increasing Ga content enhances grain boundary cohesion, relating to improved ductility. The methodology to trigger, trace, and simulate defect transformation at atomic resolution enables a systematic development of defect phase diagrams, providing a valuable tool to utilize chemical complexity and phase transformations at defects.
Determination of five-parameter grain boundary characteristics in nanocrystalline Ni-W by scanning precession electron diffraction tomography Patrick Harrison, Saurabh Mohan Das, William Goncalves, Alessandra da Silva, Xinren Chen, Nicola Viganò, Christian H. Liebscher, Wolfgang Ludwig, Xuyang Zhou, Edgar F. Rauch Ultramicroscopy, 2024 • The 3D grain microstructure of a twinned nickel-tungsten alloy nano polycrystalline tip has been reconstructed using electron diffraction signals. • The five-parameter grain boundary characteristic of the interfaces were derived from the scanning precession electron diffraction dataset. • An automated post-processing step identifies and deselects reflections common to overlapping crystals to improve the reconstruction of their virtual dark-field images. • A 3D Hough transform is proposed to determine the orientation of planar interfaces. Determining the full five-parameter grain boundary characteristics from experiments is essential for understanding grain boundaries impact on material properties, improving related models, and designing advanced alloys. However, achieving this is generally challenging, in particular at nanoscale, due to their 3D nature. In our study, we successfully determined the grain boundary characteristics of an annealed nickel-tungsten alloy (NiW) nanocrystalline needle-shaped specimen (tip) containing twins using Scanning Precession Electron Diffraction (SPED) Tomography. The presence of annealing twins in this face-centered cubic (fcc) material gives rise to common reflections in the SPED diffraction patterns, which challenges the reconstruction of orientation-specific virtual dark field (VDF) images required for tomographic reconstruction of the 3D grain shapes. To address this, an automated post-processing step identifies and deselects these shared reflections prior to the reconstruction of the VDF images. Combined with appropriate intensity normalization and projection alignment procedures, this approach enables high-fidelity 3D reconstruction of the individual grains contained in the needle-shaped sample volume. To probe the accuracy of the resulting boundary characteristics, the twin boundary surface normal directions were extracted from the 3D voxelated grain boundary map using a 3D Hough transform. For the sub-set of coherent Σ3 boundaries, the expected {111} grain boundary plane normals were obtained with an angular error of <3° for boundary sizes down to 400 nm². This work advances our ability to precisely characterize and understand the complex grain boundaries that govern material properties.
Quasi-“In Situ” Analysis of the Reactive Liquid-Solid Interface during Magnesium Corrosion Using Cryo-Atom Probe Tomography Tim M. Schwarz, Jing Yang, Leonardo S. Aota, Eric Woods, Xuyang Zhou, Jörg Neugebauer, Mira Todorova, Ingrid McCarroll, Baptiste Gault Advanced Materials, 2024 The early stages of corrosion occurring at liquid‐solid interfaces control the evolution of the material's degradation process, yet due to their transient state, their analysis remains a formidable challenge. Here corrosion tests are performed on a MgCa alloy, a candidate material for biodegradable implants using pure water as a model system. The corrosion reaction is suspended by plunge freezing into liquid nitrogen. The evolution of the early‐stage corrosion process on the nanoscale by correlating cryo‐atom probe tomography (APT) with transmission‐electron microscopy (TEM) and spectroscopy, is studied. The outward growth of Mg hydroxide Mg(OH)2 and the inward growth of an intermediate corrosion layer consisting of hydrloxides of different compositions, mostly monohydroxide Mg(OH) instead of the expected MgO layer, are observed. In addition, Ca partitions to these newly formed hydroxides and oxides. Density‐functional theory calculations suggest a domain of stability for this previously experimental unreported Mg(OH) phase. This new approach and these new findings advance the understanding of the early stages of magnesium corrosion, and in general reactions and processes at liquid‐solid interfaces, which can further facilitate the development of corrosion‐resistant materials or better control of the biodegradation rate of future implants.
Microstructure and phase transformation behavior of Ti40Zr40Ni20 alloy melt-spun ribbons Cailiao Rechuli Xuebao Transactions of Materials and Heat Treatment, 2014
Operando and Atomic-Scale Design of Recyclable Functional Materials for a Circular Catalyst Economy Y Kang, X Chen, G Dehm, B Gault, X Zhou, D Raabe Sustainability and Circular Economy in Materials Science and Technology , 2025 2025
Solid–Solid Catalysis in Sustainable Alloy Synthesis D Raabe, X Chen, B Bienvenu, T Yang, B Gault, S Wei, X Zhou 2025
On the atomic nature of complex dislocation locks in C15 Laves phases G Liu, SH Lee, CH Liebscher, S Zhang, X Zhou, JS Lee, S Wei, ... Acta Materialia, 121700 , 2025 2025 Citations: 3
Cr-induced phase instability and hierarchical microstructure development in Co-based superalloys E Zaiser, W Meng, X Zhou, L Mantha, MJ Pavel, S Neumeier, Y Long, ... Journal of Materials Science & Technology , 2025 2025 Citations: 1
APT Calibrator: A Multifunctional C# Software Application for Reconstruction Calibration in Atom Probe Tomography X Chen, Y Li, E Woods, X Zhou, B Gault Microscopy and Microanalysis 31 (5), ozaf092 , 2025 2025
Secondary grain boundary dislocations alter segregation energy spectra X Chen, W Gonçalves, Y Hu, Y Gao, P Harrison, G Dehm, B Gault, ... Nature Communications 16 (1), 8422 , 2025 2025 Citations: 9
In-situ insights into interfacial processes at reactive liquid-solid interface during magnesium corrosion using cryo-atom probe tomography T Schwarz, J Yang, L Shoji Aota, E Woods, X Zhou, J Neugebauer, ... EuroMat 2025 conference , 2025 2025
New insights into the reactive liquid-solid interface during magnesium corrosion using cryo-atom probe tomography T Schwarz, J Yang, L Shoji Aota, E Woods, X Zhou, J Neugebauer, ... EUROCORR 2025 Annular Congress of the European Federation of Corrosion , 2025 2025
Boron triggers grain boundary structural transformation in steel X Zhou, S Kumar, S Zhang, X Chen, B Gault, G Dehm, T Hickel, D Raabe Nature Communications 16 (1), 6927 , 2025 2025 Citations: 21
Correlating Grain Boundary Character and Composition in 3‐Dimensions Using 4D‐Scanning Precession Electron Diffraction and Atom Probe Tomography SM Das, P Harrison, S Kiranbabu, X Zhou, W Ludwig, EF Rauch, ... Small Methods 9 (5), 2401650 , 2025 2025 Citations: 4
Complexions at the iron-magnetite interface X Zhou, B Bienvenu, Y Wu, A Kwiatkowski da Silva, C Ophus, D Raabe Nature Communications 16 (1), 2705 , 2025 2025 Citations: 16
Grain Boundary Transformation Induced by Boron Segregation X Zhou, S Kumar, X Chen, B Gault, G Dehm, T Hickel, D Raabe Nature Communications 16, 1-14 , 2025 2025
Materials design by constructing phase diagrams for defects X Zhou, P Mathews, B Berkels, W Delis, S Saood, ... Advanced Materials 37 (3), 2402191 , 2025 2025 Citations: 25
Determination of five-parameter grain boundary characteristics in nanocrystalline Ni-W by scanning precession electron diffraction tomography P Harrison, SM Das, W Goncalves, A da Silva, X Chen, N Viganò, ... Ultramicroscopy 267, 114038 , 2024 2024 Citations: 3
Correlating grain boundary character and composition in 3-dimensions using 4D-scanning precession electron diffraction and atom probe tomography SM Das, P Harrison, S Kiranbabu, X Zhou, W Ludwig, EF Rauch, ... arXiv preprint arXiv:2409.01753 , 2024 2024 Citations: 1
cryo-atom probe tomography; quasi-'in situ'analysis of the reactive liquid-solid interface during Mg corrosion T Schwarz, L Shoji Aota, E Woods, X Zhou, I McCarroll, B Gault 16th Biometal 2024 Symposium , 2024 2024
Quasi‐“in situ” analysis of the reactive liquid‐solid interface during magnesium corrosion using cryo‐atom probe tomography TM Schwarz, J Yang, LS Aota, E Woods, X Zhou, J Neugebauer, ... Advanced Materials 36 (32), 2401735 , 2024 2024 Citations: 24
Determination of five-parameter grain boundary characteristics in nanocrystalline Ni-W by Scanning Precession Electron Diffraction Tomography EF Rauch, P Harrison, SM Das, W Goncalves, A Da Silva, X Chen, ... arXiv preprint arXiv:2407.08251 , 2024 2024 Citations: 1
Exploring the Relationship Between Grain Boundary Structure and Chemical Composition at the Atomic Level X Zhou, T Hickel, B Gault, C Ophus, C Liebscher, G Dehm, D Raabe International Conference on Intergranular and Interphase Boundaries in … , 2024 2024
Analysis of the reactive solid-liquid interface during the corrosion of magnesium at the near atomic level using cryo-atom probe tomography T Schwarz, J Yang, LS Aota, E Woods, X Zhou, J Neugebauer, ... Aqueous Corrosion Gordon Research Conference (GRC) 2024, Corrosion … , 2024 2024
MOST CITED SCHOLAR PUBLICATIONS
Ultrastrong and ductile soft magnetic high‐entropy alloys via coherent ordered nanoprecipitates L Han, Z Rao, IR Souza Filho, F Maccari, Y Wei, G Wu, A Ahmadian, ... Advanced Materials 33 (37), 2102139 , 2021 2021 Citations: 202
A novel soft‐magnetic B2‐based multiprincipal‐element alloy with a uniform distribution of coherent body‐centered‐cubic nanoprecipitates Y Ma, Q Wang, X Zhou, J Hao, B Gault, Q Zhang, C Dong, TG Nieh Advanced Materials 33 (14), 2006723 , 2021 2021 Citations: 140
Beyond solid solution high‐entropy alloys: tailoring magnetic properties via spinodal decomposition Z Rao, B Dutta, F Körmann, W Lu, X Zhou, C Liu, AK da Silva, U Wiedwald, ... Advanced Functional Materials 31 (7), 2007668 , 2021 2021 Citations: 128
Revisiting stress-corrosion cracking and hydrogen embrittlement in 7xxx-Al alloys at the near-atomic-scale M López Freixes, X Zhou, H Zhao, H Godin, L Peguet, T Warner, B Gault Nature communications 13 (1), 4290 , 2022 2022 Citations: 126
Grain boundary specific segregation in nanocrystalline Fe (Cr) X Zhou, X Yu, T Kaub, RL Martens, GB Thompson Scientific reports 6 (1), 34642 , 2016 2016 Citations: 110
Spinodal decomposition in nanocrystalline alloys X Zhou, RD Kamachali, BL Boyce, BG Clark, D Raabe, GB Thompson Acta Materialia 215, 117054 , 2021 2021 Citations: 76
On the atomic solute diffusional mechanisms during compressive creep deformation of a Co-Al-W-Ta single crystal superalloy J He, CH Zenk, X Zhou, S Neumeier, D Raabe, B Gault, SK Makineni Acta Materialia 184, 86-99 , 2020 2020 Citations: 74
Quantitative three-dimensional imaging of chemical short-range order via machine learning enhanced atom probe tomography Y Li, Y Wei, Z Wang, X Liu, T Colnaghi, L Han, Z Rao, X Zhou, L Huber, ... Nature Communications 14 (1), 7410 , 2023 2023 Citations: 70
Atom probe analysis of electrode materials for Li-ion batteries: Challenges and ways forward SH Kim, S Antonov, X Zhou, LT Stephenson, C Jung, AA El-Zoka, ... Journal of Materials Chemistry A 10 (9), 4926-4935 , 2022 2022 Citations: 66
Role of grain boundary character and its evolution on interfacial solute segregation behavior in nanocrystalline Ni-P A Gupta, X Zhou, GB Thompson, GJ Tucker Acta Materialia 190, 113-123 , 2020 2020 Citations: 66
Gibbs Adsorption and Zener Pinning Enable Mechanically Robust High‐Performance Bi 2 Te 3 ‐Based Thermoelectric Devices C Zhang, Q Lai, W Wang, X Zhou, K Lan, L Hu, B Cai, M Wuttig, J He, ... Advanced Science 10 (26), 2302688 , 2023 2023 Citations: 59
Aluminum depletion induced by co-segregation of carbon and boron in a bcc-iron grain boundary A Ahmadian, D Scheiber, X Zhou, B Gault, CH Liebscher, L Romaner, ... Nature communications 12 (1), 6008 , 2021 2021 Citations: 58
Under-stoichiometric cementite in decomposing binary Fe-C pearlite exposed to rolling contact fatigue PY Tung, X Zhou, D Mayweg, L Morsdorf, M Herbig Acta Materialia 216, 117144 , 2021 2021 Citations: 58
Composition-dependent apparent activation-energy and sluggish grain-growth in high entropy alloys B Gwalani, R Salloom, T Alam, SG Valentin, X Zhou, G Thompson, ... Materials Research Letters 7 (7), 267-274 , 2019 2019 Citations: 55
A molecular dynamics study on stress generation during thin film growth X Zhou, X Yu, D Jacobson, GB Thompson Applied Surface Science 469, 537-552 , 2019 2019 Citations: 53
The hidden structure dependence of the chemical life of dislocations X Zhou, JR Mianroodi, A Kwiatkowski da Silva, T Koenig, GB Thompson, ... Science advances 7 (16), eabf0563 , 2021 2021 Citations: 52
Hydrogen-assisted decohesion associated with nanosized grain boundary κ-carbides in a high-Mn lightweight steel MN Elkot, B Sun, X Zhou, D Ponge, D Raabe Acta Materialia 241, 118392 , 2022 2022 Citations: 50
Enhanced resistance to hydrogen embrittlement in a CrCoNi-based medium-entropy alloy via grain-boundary decoration of boron XH Chen, XQ Zhuang, JW Mo, JY He, T Yang, XY Zhou, WH Liu Materials Research Letters 10 (4), 278-286 , 2022 2022 Citations: 43
Atomic motifs govern the decoration of grain boundaries by interstitial solutes X Zhou, A Ahmadian, B Gault, C Ophus, CH Liebscher, G Dehm, D Raabe Nature communications 14 (1), 3535 , 2023 2023 Citations: 42
Understanding the degradation of a model Si anode in a Li-ion battery at the atomic scale SH Kim, K Dong, H Zhao, AA El-Zoka, X Zhou, EV Woods, F Giuliani, ... The journal of physical chemistry letters 13 (36), 8416-8421 , 2022 2022 Citations: 42
