Article
Nanoscience & Nanotechnology
Nitin P. Wasekar
Summary: This study explains the higher corrosion rates of nanocrystalline passivating metals in a NaCl environment when the grain size is below 10 nm. A simple model correlating grain size with corrosion current and the contribution from triple junctions is proposed. The higher corrosion rate below the critical grain size is attributed to the presence of a high volume fraction of triple junctions, demonstrating an inverse Hall-Petch type (corrosion) relation. The proposed relationship reveals the application range of nanocrystalline metals requiring improved corrosion resistance.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Christopher A. Schuh, Ke Lu
Summary: Two major strategies, grain-boundary alloying and achieving low-energy crystallographic grain-boundary structures, have led to effective and implementable stable nanocrystalline materials, pointing to many directions for future advancements in the field.
Article
Materials Science, Multidisciplinary
Zirong Peng, Thorsten Meiners, Yifeng Lu, Christian H. Liebscher, Aleksander Kostka, Dierk Raabe, Baptiste Gault
Summary: Grain boundaries are common microstructural imperfections in polycrystalline and nanocrystalline materials, affecting their properties and stabilities. Research has found that fast diffusion primarily occurs in the core region of grain boundaries, while segregated solute atoms occupy a larger spatial range. The formation of secondary phase nuclei at matrix grain boundaries is influenced by their complex three-dimensional topology.
Article
Materials Science, Multidisciplinary
Matthew J. Patrick, Gregory S. Rohrer, Ooraphan Chirayutthanasak, Sutatch Ratanaphan, Eric R. Homer, Gus L. W. Hart, Yekaterina Epshteyn, Katayun Barmak
Summary: Grain boundary character distributions (GBCD) can be measured from microcrystalline samples using electron backscatter diffraction (EBSD) and can be used to reconstruct relative grain boundary energy distributions (GBED) based on the 3D geometry of triple lines, assuming the force balance condition is satisfied. However, for nanocrystalline thin films, the GBED cannot be extracted effectively using orientation mapping via precession enhanced electron diffraction (PED). In this study, the relative energy extraction technique was adapted to PED data and the results showed that the GBED extracted from these films do not correlate with energies calculated using molecular dynamics (MD) or with the experimentally determined GBCD. This suggests that additional geometric factors contribute to determining the triple junction geometry and boundary network structure in these films.
Article
Nanoscience & Nanotechnology
Kazuho Okada, Akinobu Shibata, Taisuke Sasaki, Hisashi Matsumiya, Kazuhiro Hono, Nobuhiro Tsuji
Summary: This study aimed to improve the resistance against hydrogen embrittlement by increasing the concentration of carbon segregated at prior austenite grain boundary (PAGB), XPAGB, in low-carbon martensitic steels. The specimens with and without carbon segregation treatment (Non-seg and Seg specimens, respectively) had similar microstructures, except for higher XPAGB in the Seg specimen. The Seg specimen exhibited higher maximum stress and smaller fraction of intergranular fracture surface under hydrogen-charged conditions, indicating that segregated carbon suppressed hydrogen accumulation and increased cohesive energy of PAGB.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Kai Liu, ShangBin Gao, ZhongHua Wang, Xiazi Xiao, Chao Jiang
Summary: This work proposes a mechanistic model to characterize the evolution of hardness in ion-irradiated nanocrystalline metals as a function of indentation depth. The model considers the contribution of grain interiors and grain boundaries to hardening, and validates the rationality and accuracy of the proposed model through comparison with experimental data.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Nutth Tuchinda, Christopher A. Schuh
Summary: Grain boundary segregation is crucial for stabilizing nanocrystalline alloys, and this study provides quantitative detail on two previously unelaborated grain size dependencies in Al(Mg) binary alloy. The findings reveal that changes in grain size affect the segregation behavior of solutes in the spectrum occupied by intergranular segregation sites, and the presence of higher-order grain junctions also contributes to grain size dependence.
Article
Materials Science, Multidisciplinary
Anna Sophie Ebner, Severin Jakob, Helmut Clemens, Reinhard Pippan, Verena Maier-Kiener, Shuang He, Werner Ecker, Daniel Scheiber, Vsevolod Razumovskiy
Summary: Grain boundary engineering is crucial in designing new materials, especially for nickel-based alloys. By combining advanced experimental and theoretical methods, the grain boundary chemistry of the 725 Ni-base alloy is revealed, providing a way to evaluate the interfacial excess based on the material's heat treatment history and chemistry.
Article
Nanoscience & Nanotechnology
Rama Srinivas Varanasi, Marta Lipinska-Chwalek, Joachim Mayer, Baptiste Gault, Dirk Ponge
Summary: The study investigates the mechanisms of austenite growth in medium manganese steel, providing evidence of manganese transport to austenite through grain boundary diffusion, grain boundary migration, and dislocation pipe diffusion. Furthermore, the influence of grain boundary misorientation on austenite growth is also reported.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Lakshmi Sravani Mantha, Benjamin. E. MacDonald, Xiaoke Mu, Andrey Mazilkin, Julia Ivanisenko, Horst Hahn, E. J. Lavernia, Shyam Katnagallu, Christian Kuebel
Summary: This study aims to establish a systematic understanding of phase evolution in face-centered cubic non-equilibrium atomic nanocrystalline alloys. The research reveals a complex succession of grain boundary segregation and depletion steps leading to the formation of a FeCo-rich secondary phase. Prior to the formation of the secondary phase, Cu, Ni, and Co segregate at grain boundaries while Fe and Mn deplete. After FeCo precipitation is triggered, Mn segregates along with Ni and Cu, while Fe and Co are depleted.
Article
Physics, Condensed Matter
Nengwen Hu, Yongfeng Huang, Kun Wang, Wangyu Hu, Wenjun Zhu, Jun Chen, Huiqiu Deng
Summary: The roles of non-/symmetric triple and quadruple junctions on the plasticity of polycrystals are examined using a phasefield crystal model. It is found that symmetric quadruple junctions contribute to the stability of the junctions during deformations, while asymmetric ones result in the formation and growth of sub-grains. The stability of triple junctions is strongly related to the misorientation angles of the associated grains.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Nanoscience & Nanotechnology
Hossein Sepehri-Amin, Kazuki Imasato, Maxwell Wood, Jimmy Jiahong Kuo, G. Jeffrey Snyder
Summary: This study investigates the microstructure of n-type Mg3Sb2-Mg3Bi2 alloys using scanning transmission electron microscopy and atom probe tomography. Nanosized compositional fluctuations and a Bi-rich phase were observed within the matrix and at the grain boundary. After annealing, the intergranular phase became sharper, resulting in greater compositional changes in the intergranular region. Annealing significantly reduced the fluctuations of Bi and Mg content within the grain, leading to increased weighted mobility and lattice thermal conductivity. The combined effect of intragrain and grain boundary effects resulted in an increased thermoelectric figure-of-merit zT.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Wei Zhang, Xuefeng Lu, Junqiang Ren, Junchen Li, Hongtao Xue, Fuling Tang, Xin Guo
Summary: Solute element segregation behavior significantly affects the mechanical properties and deformation mechanism of nanocrystals. By using molecular dynamics, we investigated the effect of segregation structure on the deformation mechanism of NiCoAl nanocrystalline. The results reveal that complete segregation of Al within the grain leads to poor grain boundary stability and ineffective hindrance of dislocation movement, resulting in inferior mechanical properties. However, when 4% of Al transitions to the grain boundary, the stability improves significantly, generating lamination structures that effectively strengthen the nanocrystals.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Materials Science, Multidisciplinary
Jacob Hohl, Pankaj Kumar, Mano Misra, Pradeep Menezes, Leslie T. Mushongera
Summary: Nanocrystalline metals can be stabilized by introducing preferential dopants to enhance the stability of the material's microstructure. Magnesium, lanthanum, and silicon are identified as effective dopant elements capable of promoting thermodynamic stability in aluminum's nanocrystalline regime.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Gashaw B. Bizana, Luis A. Barrales-Mora
Summary: The grain growth in nanosized polycrystalline Al was investigated using molecular dynamics. The study analyzed the volumetric growth rate of grains based on their size, topology, and mean curvature. It was discovered that grains with approximately 15 faces have zero mean curvature, and their volume remains unchanged. Additionally, the integral mean curvature of grains was found to be correlated with the difference in face numbers between grains and their neighbors. The study also observed discrepancies between theoretical predictions and measured growth rates, especially for grains with significant size differences and high face number differences.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Shiv Prakash Singh, Mohammed Reda Chellali, Leonardo Velasco, Yulia Ivanisenko, Evgeniy Boltynjuk, Herbert Gleiter, Horst Hahn
JOURNAL OF ALLOYS AND COMPOUNDS
(2020)
Article
Materials Science, Multidisciplinary
Sree Harsha Nandam, Omar Adjaoud, Ruth Schwaiger, Yulia Ivanisenko, Mohammed Reda Chellali, Di Wang, Karsten Albe, Horst Hahn
Article
Engineering, Environmental
Dambarudhar Parida, Pietro Simonetti, Ruggero Frison, Ezgi Bulbul, Stefanie Altenried, Yadira Arroyo, Zoltan Balogh-Michels, Walter Caseri, Qun Ren, Rudolf Hufenus, Sabyasachi Gaan
CHEMICAL ENGINEERING JOURNAL
(2020)
Article
Multidisciplinary Sciences
Xinglong Ye, Harish K. Singh, Hongbin Zhang, Holger Gesswein, Mohammed Reda Chellali, Ralf Witte, Alan Molinari, Konstantin Skokov, Oliver Gutfleisch, Horst Hahn, Robert Kruk
NATURE COMMUNICATIONS
(2020)
Article
Chemistry, Multidisciplinary
Xinglong Ye, Fengkai Yan, Lukas Schaefer, Di Wang, Holger Gesswein, Wu Wang, Mohammed Reda Chellali, Leigh T. Stephenson, Konstantin Skokov, Oliver Gutfleisch, Dierk Raabe, Horst Hahn, Baptiste Gault, Robert Kruk
Summary: Hydrogen atoms play a critical role in permanent magnets, and engineering grain boundaries can achieve the giant magnetoelectric effect in these magnets.
ADVANCED MATERIALS
(2021)
Article
Multidisciplinary Sciences
T. M. Schwarz, E. M. Weikum, K. Meng, E. Hadjixenophontos, C. A. Dietrich, J. Kaestner, P. Stender, G. Schmitz
SCIENTIFIC REPORTS
(2020)
Article
Chemistry, Multidisciplinary
Thomas Gischkat, Daniel Schachtler, Igor Stevanovic, Zoltan Balogh-Michels, Roelene Botha, Andreas Baechli, Marco Cucinelli, Andre Mocker, Martin Gutsche, Sven Guenther, Philipp Alder, Bernd Eiermann
APPLIED SCIENCES-BASEL
(2020)
Article
Chemistry, Multidisciplinary
Igor Stevanovic, Zoltan Balogh-Michels, Andreas Bachli, Valentin J. Wittwer, Thomas Sudmeyer, Alexander Stuck, Thomas Gischkat
Summary: Ion beam sputtered hafnia is a preferred high index coating material for laser applications due to its mostly amorphous structure and adequate laser-induced damage threshold. Research shows that the stress of the film increases with the ion energy of the assisting ion source, leading to different laser-induced damage thresholds and morphologies depending on the stress state.
APPLIED SCIENCES-BASEL
(2021)
Article
Optics
Zoltan Balogh-Michels, Igor Stevanovic, Aurelio Borzi, Andreas Bachli, Daniel Schachtler, Thomas Gischkat, Antonia Neels, Alexander Stuck, Roelene Botha
Summary: The study shows that thermal treatment of hafnia has an impact on the laser-induced damage threshold (LIDT), with a 1-hour treatment at 773K reducing the 0% LIDT, while a 5-hour treatment significantly increases the LIDT values.
JOURNAL OF THE EUROPEAN OPTICAL SOCIETY-RAPID PUBLICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Kuan Meng, Tim M. Schwarz, Eric M. Weikum, Patrick Stender, Guido Schmitz
Summary: Atom probe tomography (APT) has been applied to study the evaporation and fragmentation behavior of simple alkane chains (n-tetradecanes), providing detailed information on the decay of molecules into smaller fragments near the tip. The complex evaporation behavior of tetradecane, with peaks observed up to C15, demonstrates the potential of APT for analysis of organic and biological soft matter. This study also reveals various dissociation tracks and subsequent decay of larger molecules in their excited state in low-field regions, expanding the application of APT in the analysis of complex materials.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Materials Science, Multidisciplinary
Helena Solodenko, Patrick Stender, Guido Schmitz
Summary: Atom probe tomography was used to investigate the fragmentation behavior of self-assembled monolayers of 1-octadecanethiol on platinum tips under different laser powers. The carbon backbone evaporates into small hydrocarbon fragments, while sulfur evaporates as single ions; carbon evaporates at lower fields compared to sulfur. Increasing laser power leads to a trend towards larger fragment sizes.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Chemistry, Physical
Thomas Gischkat, Max Dobeli, Andreas Bachli, Roelene Botha, Zoltan Balogh-Michels
Summary: The wetting properties of ion-beam-sputtered Yttria thin films were investigated in this work, with water contact angles ranging from 67 to 96 degrees. The concentration of embedded argon atoms was found to influence the contact angle.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Patrick Stender, Helena Solodenko, Andreas Weigel, Irdi Balla, Tim Maximilian Schwarz, Jonas Ott, Manuel Roussell, Yug Joshi, Rueya Duran, Mohammad Al-Shakran, Timo Jacob, Guido Schmitz
Summary: Atomic probe tomography (APT) is an instrument capable of generating three-dimensional chemical maps with atomic resolution. In this study, a new modular instrument concept is described, which allows the direct attachment of APT to a dual-beam SEM microscope, enabling fast and flexible sample transfer and configuration. The instrument is optimized for handling cryo-samples and comes with its own software for evaluation and reconstruction.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Chemistry, Physical
Nico Segreto, Tim M. Schwarz, Carolin A. Dietrich, Patrick Stender, Robin Schuldt, Guido Schmitz, Johannes Kaestner
Summary: This study investigates the field evaporation process of frozen water in atom probe tomography through density functional simulations. The simulation results provide new insights into the complex evaporation behavior of water in high electrical fields and explain the tailing effect observed in previous experiments caused by the molecular structure.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Multidisciplinary Sciences
Baptiste Gault, Ann Chiaramonti, Oana Cojocaru-Miredin, Patrick Stender, Renelle Dubosq, Christoph Freysoldt, Surendra Kumar Makineni, Tong Li, Michael Moody, Julie M. Cairney
Summary: APT provides three-dimensional compositional mapping with sub-nanometre resolution and high sensitivity for all elements. The overview covers the development, specimen preparation, data reconstruction, analysis, applications, performance underpinning, strengths, limitations, and potential improvements of APT. Future advancements aim for true atomic-scale tomography through new specimen preparation methods, novel technologies, and interoperability with complementary techniques.
NATURE REVIEWS METHODS PRIMERS
(2021)
