Article
Materials Science, Multidisciplinary
Xiaoyuan Yuan, Yuan Wu, Meisa Zhou, Xiongjun Liu, Hui Wang, Suihe Jiang, Xiaobin Zhang, Honghui Wu, Xiaochun Liu, Zipan Chen, Xiangqi Xu, Zhaoping Lu
Summary: In this study, it was discovered that the mechanical properties of TiZrHfNb high-entropy alloys can greatly vary with the impurity content in the samples, even when using high-purity raw materials. Oxygen impurity mainly increases the yield stress through strong interstitial hardening, while the deterioration of ductility is closely associated with the content of metalloid elements B, C, and Si. The analysis revealed that these metalloid elements tend to segregate at grain boundaries and enhance the aggregation of Zr and Ti, leading to grain boundary embrittlement and brittle fracture. This study demonstrates the importance of strict control over impurity contents in refractory high-entropy alloys during production to improve their mechanical performance stability.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Byungchul Kang, Taeyeong Kong, Nguyen Huy Dan, Doan Dinh Phuong, Ho Jin Ryu, Soon Hyung Hong
Summary: The addition of boron to a refractory high-entropy alloy (RHEA) significantly improves its yield strength and ductility, transforming the fracture surface and enhancing the material's ductility due to boron segregation along grain boundaries. Boron segregation contributes to increased grain boundary cohesion, leading to enhanced yield strength. The improved yield strength attributed to boron doping is a result of the combined effects of Orowan, dislocation, and boron interstitial strengthening mechanisms.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Nutth Tuchinda, Christopher A. Schuh
Summary: The vibrational contributions to grain boundary segregation have been calculated for binary Ni polycrystals with various solutes. A multiscale approach was used to accurately assess the site energies and entropies. The results emphasize the importance of considering vibrational entropy in segregation calculations. A strong linear correlation between site segregation energy and vibrational entropy was observed in polycrystals, promising a simplification of segregation calculations in general.
Article
Materials Science, Multidisciplinary
Shuo Wang, Xiang Cai, Zan Wang, Jia Ju, Jian Zhou, Feng Xue
Summary: This study investigates the impact of solute Al on the penetration of Cu atoms into the Fe grain boundary in the Fe-Cu embrittlement system through molecular dynamics simulations. Additionally, first principle density functional theory calculations are performed to determine the binding properties and electronic structure of GBs doped with solute atoms. The mechanisms of inhibiting liquid metal embrittlement cracks in the Fe-Cu system by Al are analyzed at the atomic scale. The results demonstrate that Al diffusion along the GB direction is much higher than that of Cu, and the preferential penetration and segregation of Al atoms act as a barrier layer.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
X. H. Chen, X. Q. Zhuang, J. W. Mo, J. Y. He, T. Yang, X. Y. Zhou, W. H. Liu
Summary: The study demonstrates that boron doping can effectively reduce the ductility loss and enhance the resistance to hydrogen embrittlement in CrCoNi medium-entropy alloy, by improving grain-boundary cohesion and reducing hydrogen diffusivity.
MATERIALS RESEARCH LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Risheng Pei, Yongchun Zou, Muhammad Zubair, Daqing Wei, Talal Al-Samman
Summary: This study investigates the synergistic effect of various alloying elements on the texture and microstructure evolution in magnesium alloys. The results demonstrate that adjusting the precipitation and solute segregation can lead to desired texture modifications.
Article
Nanoscience & Nanotechnology
Risheng Pei, Zhuocheng Xie, Sangbong Yi, Sandra Korte-Kerzel, Julien Guenole, Talal Al-Samman
Summary: Solute segregation at grain boundaries in magnesium alloys with multiple substitutional elements has a strong impact on various material characteristics. This study investigates the compositional inhomogeneity of six different grain boundaries using experimental and simulation techniques. The results reveal that the solute concentration of Nd in Mg varies between 2 and 5 at.%, and this variation is observed for different grain boundary orientations and within the grain boundary plane. Correlated atomistic simulations suggest that this inhomogeneous segregation behavior is caused by local atomic rearrangements within the grain boundaries.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
P. Lejcek, S. Hofmann
Summary: The article introduces and discusses the phenomenon of entropy-dominated grain boundary segregation, providing numerous examples such as alpha-iron-based alloys and other host materials. It explores the consequences of this phenomenon for grain size stabilization and intergranular embrittlement.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Nanoscience & Nanotechnology
Diana Farkas
Summary: Atomistic simulation studies on deformation behavior in a model quinary high entropy FCC alloy show that local composition fluctuations in random alloys make dislocation glide more difficult, resulting in higher strength and less plastic deformation compared to average atom materials.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
Lei Wang, Reza Darvishi Kamachali
Summary: The desire for developing high-entropy alloys has raised concerns about their safe application. This study investigates the co-segregation phenomena in multi-component alloys and quantitatively simulates the grain boundary spinodal decomposition. The concept of co-segregation maps is also introduced for grain boundary segregation screening and design in multi-component alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Liujie Yang, Xingyu Feng, Jiayu Xie, Hongchen Qian, Xianchao Hao, Wenjun Kuang
Summary: The grain boundary corrosion behavior of Ni15Cr alloy in 650°C/1bar CO2 gas was investigated. It was found that the oxidation behavior of coherent twin boundary is similar to that of grain matrix, while the incoherent twin boundary is prone to preferential intergranular oxidation. Low angle GB is also susceptible to intergranular oxidation, although it can induce GB migration and result in a protective scale. In contrast, random high angle GB is immune to intergranular oxidation.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Physical
Spencer Dahl, Toshihiro Aoki, Amitava Banerjee, Blas Pedro Uberuaga, Ricardo H. R. Castro
Summary: Lithium-ion batteries are crucial for improving energy storage solutions, and understanding the stability of interfaces plays a key role in enhancing battery capacity and cyclability. Chemical modification of interfaces offers the opportunity to create metastable states in cathodes to inhibit degradation. Atomistic simulations are effective in evaluating dopant interfacial segregation trends and can be used as a predictive tool for cathode design. The study investigated the segregation potential and stabilization effect of dopants in LiCoO(2) through computational analysis of surfaces and grain boundaries.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Thomas P. Matson, Christopher A. Schuh
Summary: In this study, a physically motived atomistic method was proposed to measure the full distribution of solute-solute interaction energies at grain boundaries in a polycrystalline environment. This method provides a rapid way to measure key interactions for non-dilute grain boundary segregation for any system with an interatomic potential.
Article
Materials Science, Multidisciplinary
Yemao Lu, Horst Hahn, Yulia Ivanisenko
Summary: In this study, a CoCrFeMnNi high-entropy alloy with reduced Cr content and the addition of 2 at% C interstitial was processed via high-pressure torsion. The results show that C atoms segregate at the boundaries of nanograins in the sample processed at room temperature, while no notable segregations of carbon were observed in the sample processed at cryogenic temperature.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Ceramics
Chunyang Wang, Mingde Qin, Tianjiao Lei, Yubin He, Kim Kisslinger, Timothy J. Rupert, Jian Luo, Huolin L. Xin
Summary: The study systematically investigated the structures and behaviors of grain boundary segregation and precipitation in high-entropy borides containing W and W-Mo. It was found that GB engineering could potentially optimize the performance of high-entropy ceramics by providing additional hardening through simultaneous GB segregation and coherent precipitation.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Multidisciplinary
F. Thiel, D. Geissler, K. Nielsch, A. Kauffmann, S. Seils, M. Heilmaier, D. Utt, K. Albe, M. Motylenko, D. Rafaja, J. Freudenberger
Article
Materials Science, Multidisciplinary
Josua Kottke, Daniel Utt, Mathilde Laurent-Brocq, Adnan Fareed, Daniel Gaertner, Loic Perriere, Lukasz Rogal, Alexander Stukowski, Karsten Albe, Sergiy Divinski, Gerhard Wilde
Article
Nanoscience & Nanotechnology
F. Thiel, D. Utt, A. Kauffmann, K. Nielsch, K. Albe, M. Heilmaier, J. Freudenberger
SCRIPTA MATERIALIA
(2020)
Article
Nanoscience & Nanotechnology
Daniel Utt, Alexander Stukowski, Maryam Ghazisaeidi
SCRIPTA MATERIALIA
(2020)
Article
Materials Science, Multidisciplinary
Won-Seok Ko, Alexander Stukowski, Raheleh Hadian, Ali Nematollahi, Jong Bae Jeon, Won Seok Choi, Gerhard Dehm, Joerg Neugebauer, Christoph Kirchlechner, Blazej Grabowski
Article
Chemistry, Physical
Luis A. Zepeda-Ruiz, Alexander Stukowski, Tomas Oppelstrup, Nicolas Bertin, Nathan R. Barton, Rodrigo Freitas, Vasily V. Bulatov
Summary: We demonstrated that crystal rotation leads to the staged hardening of metals, while the basic mechanisms of dislocation behavior remain consistent across all stages of metal hardening.
Article
Materials Science, Multidisciplinary
Tom Keil, Daniel Utt, Enrico Bruder, Alexander Stukowski, Karsten Albe, Karsten Durst
Summary: Solid solution hardening in high entropy alloys was studied using diffusion couples and nanoindentation in the Cantor alloy. The Labusch model and Varvenne model were used to analyze the composition-dependent hardness, confirming Cr as the most potent strengthening element. Introducing a concentration-dependent strain-hardening factor led to a good agreement between experimental and predicted yield strength in the Varvenne model.
JOURNAL OF MATERIALS RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
Arne J. Klomp, Alexander Stukowski, Ralf Mueller, Karsten Albe, Felix Diewald
Summary: The influence of surface stresses on the deformation behavior of nanoporous metals was investigated in this study using molecular statics simulations and an elastic continuum model. It was found that the elastic response is sensitive to the loading direction, showing asymmetric behavior, and high von Mises stresses were observed at sites where dislocation activity begins.
Article
Multidisciplinary Sciences
Daniel Utt, Subin Lee, Yaolong Xing, Hyejin Jeong, Alexander Stukowski, Sang Ho Oh, Gerhard Dehm, Karsten Albe
Summary: By experiments and simulations, this study investigates the reasons for dislocation pinning in high-entropy alloys. The research finds that the critical stress required for dislocation glide is proportional to the density of high local Peierls friction.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
J. Freudenberger, F. Thiel D. Utt, K. Albe, A. Kauffmann, S. Seils, M. Heilmaier
Summary: Little research has been done on the effect of solid solution strengthening for alloys with non-equimolar composition, which is crucial for verifying theories on solid solution strengthening for highly concentrated alloys. This study compares experimental results with a model for a series of alloys with deliberately adjusted composition, highlighting both agreeable and discrepant results.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Y. Liu, K. Zweiacker, C. Liu, J. T. McKeown, J. M. K. Wiezorek
Summary: The evolution of rapid solidification microstructure and solidification interface velocity of hypereutectic Al-20at.%Cu alloy after laser melting has been studied experimentally. It was found that the formation of microstructure was dominated by eutectic, alpha-cell, and banded morphology grains, and the growth modes changed with increasing interface velocity.
Article
Materials Science, Multidisciplinary
Bharat Gwalani, Julian Escobar, Miao Song, Jonova Thomas, Joshua Silverstein, Andrew Chihpin Chuang, Dileep Singh, Michael P. Brady, Yukinori Yamamoto, Thomas R. Watkins, Arun Devaraj
Summary: Castable alumina forming austenitic alloys exhibit superior creep life and oxidation resistance at high temperatures. This study reveals the mechanism behind the enhanced creep performance of these alloys by suppressing primary carbide formation and offers a promising alloy design strategy for high-temperature applications.
Article
Materials Science, Multidisciplinary
Jian Song, Qi Zhang, Songsong Yao, Kunming Yang, Houyu Ma, Jiamiao Ni, Boan Zhong, Yue Liu, Jian Wang, Tongxiang Fan
Summary: Recent studies have shown that achieving an atomically flat surface for metals can greatly improve their oxidation resistance and enhance their electronic-optical applications. Researchers have explored the use of graphene as a covering layer to achieve atomically flat surfaces. They found that high-temperature deposited graphene on copper surfaces formed mono-atomic steps, while annealed copper and transferred graphene on copper interfaces formed multi-atomic steps.
Article
Materials Science, Multidisciplinary
Jennifer A. Glerum, Jon-Erik Mogonye, David C. Dunand
Summary: Elemental powders of Al, Ti, Sc, and Zr are blended and processed via laser powder-bed fusion to create binary and ternary alloys. The microstructural analysis and mechanical testing show that the addition of Ti results in the formation of primary precipitates, while the addition of Sc and Zr leads to the formation of fine grain bands. The Al-0.25Ti-0.25Zr alloy exhibits comparable strain rates to Al-0.5Zr at low stresses, but significantly higher strain rates at higher stresses during compressive creep testing. Finite element modeling suggests that the connectivity of coarse and fine grain regions is a critical factor affecting the creep resistance of the alloys.
Article
Materials Science, Multidisciplinary
P. Jannotti, B. C. Hornbuckle, J. T. Lloyd, N. Lorenzo, M. Aniska, T. L. Luckenbaugh, A. J. Roberts, A. Giri, K. A. Darling
Summary: This work characterizes the thermo-mechanical behavior of bulk nanocrystalline Cu-Ta alloys under extreme conditions. The experiments reveal that the alloys exhibit unique mechanical properties, behaving differently from conventional nanocrystalline Cu. They do not undergo grain coarsening during extrusion and exhibit behavior similar to coarse-grained Cu.
Article
Materials Science, Multidisciplinary
Yiqing Wei, Jingwei Li, Daliang Zhang, Bin Zhang, Zizhen Zhou, Guang Han, Guoyu Wang, Carmelo Prestipino, Pierric Lemoine, Emmanuel Guilmeau, Xu Lu, Xiaoyuan Zhou
Summary: This study proposes a new strategy to modify microstructure by phase regulation, which can simultaneously enhance carrier mobility and reduce lattice thermal conductivity. The addition of Cu in layered SnSe2 induces a phase transition that leads to increased grain size and reduced stacking fault density, resulting in improved carrier mobility and lower lattice thermal conductivity.
Article
Materials Science, Multidisciplinary
Jia Chen, Zhengyu Zhang, Eitan Hershkovitz, Jonathan Poplawsky, Raja Shekar Bhupal Dandu, Chang-Yu Hung, Wenbo Wang, Yi Yao, Lin Li, Hongliang Xin, Honggyu Kim, Wenjun Cai
Summary: In this study, the structural origin of the pH-dependent repassivation mechanisms in multi-principal element alloys (MPEA) was investigated using surface characterization and computational simulations. It was found that selective oxidation in acidic to neutral solutions leads to enhanced nickel enrichment on the surface, resulting in reduced repassivation capability and corrosion resistance.
Article
Materials Science, Multidisciplinary
X. Y. Xu, C. P. Huang, H. Y. Wang, Y. Z. Li, M. X. Huang
Summary: The limited slip systems of magnesium (Mg) and its alloys hinder their wide applications. By conducting tensile straining experiments, researchers discovered a rate-dependent transition in the dislocation mechanisms of Mg alloys. At high strain rates, glissile dislocations dominate, while easy-glide dislocations dominate at low strain rates. Abundant glissile dislocations do not necessarily improve ductility.
Article
Materials Science, Multidisciplinary
M. S. Szczerba, M. J. Szczerba
Summary: Inverse temperature dependences of the detwinning stress were observed in face-centered cubic deformation twins in Cu-8at.%Al alloy. The detwinning stress increased with temperature when the pi detwinning mode was involved, but decreased when the pi/3 mode was involved. The dual effect of temperature on the detwinning stress was due to the reduction of internal stresses pre-existing within the deformation twins. The complete reduction of internal stresses at about 530 degrees C led to the equivalence of the critical stresses of different detwinning modes and a decrease in the yield stress anisotropy of the twin/matrix structure.
Article
Materials Science, Multidisciplinary
Taowen Dong, Tingting Qin, Wei Zhang, Yaowen Zhang, Zhuoran Feng, Yuxiang Gao, Zhongyu Pan, Zixiang Xia, Yan Wang, Chunming Yang, Peng Wang, Weitao Zheng
Summary: The interaction between the electrode and the electric double layer (EDL) significantly influences the energy storage mechanism. By studying the popular alpha-Fe2O3 electrode and the EDL interaction, we find that the energy storage mechanism of the electrode can be controlled by modulating the EDL.
Article
Materials Science, Multidisciplinary
Matthew R. Barnett, Jun Wang, Sitarama R. Kada, Alban de Vaucorbeil, Andrew Stevenson, Marc Fivel, Peter A. Lynch
Summary: The elastic-plastic transition in magnesium alloy Mg-4.5Zn exhibits bursts of deformation, which are characterized by sudden changes in grain orientation. These bursts occur in a coordinated manner among nearby grains, with the highest burst rate observed at the onset of full plasticity. The most significant burst events are associated with twinning, supported by the observation of twinned structures using electron microscopy. The bursts are often preceded and followed by a stasis in peak movement, indicating a certain "birth size" for twins upon formation and subsequent growth at a later stage.
Article
Materials Science, Multidisciplinary
Vaidehi Menon, Sambit Das, Vikram Gavini, Liang Qi
Summary: Understanding solute segregation thermodynamics is crucial for investigating grain boundary properties. The spectral approach and thermodynamic integration methods can be used to predict solute segregation behavior at grain boundaries and compare with experimental observations, thus aiding in alloy design and performance control.
Article
Materials Science, Multidisciplinary
Feiyu Qin, Lei Hu, Yingcai Zhu, Yuki Sakai, Shogo Kawaguchi, Akihiko Machida, Tetsu Watanuki, Yue-Wen Fang, Jun Sun, Xiangdong Ding, Masaki Azuma
Summary: This study reports on the negative and zero thermal expansion properties of Cd2Re2O7 and Cd1.95Ni0.05Re2O7 materials, along with their ultra-low thermal conductivity. Through investigations of their structures and phonon calculations, the synergistic effect of local structure distortion and soft phonons is revealed as the key to achieving these distinctive properties.
Article
Materials Science, Multidisciplinary
Thomas Beerli, Christian C. Roth, Dirk Mohr
Summary: A novel testing system for miniature specimens is designed to characterize the plastic response of materials for which conventional full-size specimens cannot be extracted. The system has an automated operation process, which reduces the damage to specimens caused by manual handling and improves the stability of the test results. The experiments show that the miniature specimens extracted from stainless steel and aluminum have high reproducibility, and the results are consistent with those of conventional-sized specimens. A correction procedure is provided to consider the influence of surface roughness and heat-affected zone caused by wire EDM.
Article
Materials Science, Multidisciplinary
Rani Mary Joy, Paulius Pobedinskas, Nina Baule, Shengyuan Bai, Daen Jannis, Nicolas Gauquelin, Marie-Amandine Pinault-Thaury, Francois Jomard, Kamatchi Jothiramalingam Sankaran, Rozita Rouzbahani, Fernando Lloret, Derese Desta, Jan D'Haen, Johan Verbeeck, Michael Frank Becker, Ken Haenen
Summary: This study investigates the influence of film microstructure and composition on the Young's modulus and residual stress in nanocrystalline diamond thin films. The results provide insights into the mechanical properties and intrinsic stress sources of these films, and demonstrate the potential for producing high-quality nanocrystalline diamond films under certain conditions.
