Article
Multidisciplinary Sciences
Shufen Chu, Pan Liu, Yin Zhang, Xiaodong Wang, Shuangxi Song, Ting Zhu, Ze Zhang, Xiaodong Han, Baode Sun, Mingwei Chen
Summary: In this study, the authors report real-time atomic-scale observations of grain boundary dislocation climb in nanostructured gold at room temperature. The climb of a dislocation is found to occur through stress-induced reconstruction of neighboring atomic columns. The proposed atomic route of dislocation climb is energetically favorable, as demonstrated by Monte Carlo simulations. The in situ observations also reveal the significance of grain boundary dislocation climb in controlling the microstructures and properties of nanostructured metals.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Fluids & Plasmas
F. S. Abril, C. J. Quimbay
Summary: The article explores the relationship between temporal fluctuation scaling (TFS) and temporal Theil scaling (TTS), and their presence in nonstationary time series. By analyzing data from financial markets, meteorology, and COVID-19 spread, the authors find that TTS is present in diffusive trajectory time series, while TFS is not.
Article
Multidisciplinary Sciences
Jie Yuan, Qihong Chen, Kun Jiang, Zhongpei Feng, Zefeng Lin, Heshan Yu, Ge He, Jinsong Zhang, Xingyu Jiang, Xu Zhang, Yujun Shi, Yanmin Zhang, Mingyang Qin, Zhi Gang Cheng, Nobumichi Tamura, Yi-feng Yang, Tao Xiang, Jiangping Hu, Ichiro Takeuchi, Kui Jin, Zhongxian Zhao
Summary: The research uncovers the precise quantitative scaling laws among the superconducting transition temperature, the linear-in-T scattering coefficient, and the doping level in electron-doped copper oxide La2-xCexCuO4, suggesting a common mechanism of the strange-metal behavior and unconventional superconductivity in these systems.
Article
Engineering, Manufacturing
K. Naresh, A. Salem, K. A. Khan, W. J. Cantwell, R. Umer
Summary: Increasing the number of prepreg layers results in a decrease in compaction and associated creep response, with higher levels of reinforcement compaction and permanent deformation observed at 90 degrees C. Lower void volume fractions were measured in 8-layer specimens compared to 4- and 12-layer specimens.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2022)
Article
Chemistry, Multidisciplinary
Huan Yao, Tianzhou Ye, Pengfei Wang, Junmei Wu, Jing Zhang, Ping Chen
Summary: This study investigates the creep process of nanocrystalline FeCrAl alloys using atomistic simulations, and analyzes the dependence of creep on temperature, stress, and grain size. It is found that under low stress conditions, grain boundary diffusion contributes more to creep than lattice diffusion, while lattice diffusion controls creep in alloys with larger grain sizes. Under medium- and high-stress conditions, grain boundary slip and dislocation motion begin to control the creep mechanism.
Article
Physics, Multidisciplinary
Jonathan A. Jackson, Nicolas Romeo, Alexander Mietke, Keaton J. Burns, Jan F. Totz, Adam C. Martin, Jorn Dunkel, Jasmin Imran Alsous
Summary: This study characterizes the dynamics of nuclear wrinkling during egg development in fruit flies. Analyzing high-resolution live imaging data, the researchers find that the angular fluctuations of cell nuclei follow a power-law scaling consistent with predictions from a nonlinear elastic shell model. They also demonstrate that nuclear wrinkling can be reversed by osmotic shock and suppressed by microtubule disruption. These findings contribute to the understanding of nuclear membrane fluctuations during early multicellular development.
Article
Materials Science, Multidisciplinary
Rishabh Duhan, Subhamita Sengupta, Ruchi Tomar, Somak Basistha, Vivas Bagwe, Chandan Dasgupta, Pratap Raychaudhuri
Summary: We report the formation of a pinned vortex liquid in a 5-nm-thick amorphous superconducting film, where some vortices remain static while others form a percolating network.
Article
Geochemistry & Geophysics
Alexander D. J. Lusk, John P. Platt, Jason A. Platt
Summary: A flow law for dislocation-dominated creep in wet quartz was derived from compiled experimental and field-based rheological data. Through statistical analysis, internally consistent parameters were computed. The study revealed different effective stress exponents for quartz deformed at high and low confining pressures, possibly due to increased activity of grain size sensitive creep.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Materials Science, Multidisciplinary
Vaclav Sklenicka, Kveta Kucharova, Petr Kral, Jiri Dvorak, Marie Kvapilova, Vera Vrtilkova, Jakub Krejci
Summary: Short-term constant stress creep tests were conducted on two zirconium Zr1%Nb cladding alloys to investigate their creep behavior in different phase regions. The microstructure of the alloys was analyzed using SEM and TEM microscopy. The stress rate exponent and the stress-dependant activation energy for creep were determined, and possible creep deformation mechanisms and creep strengthening mechanisms were discussed. Three distinct stress regions were identified based on the controlling creep deformation mechanisms.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Chemistry, Physical
Sijia Hu, Qinghuan Huo, Chunyu Wang, Yuxiu Zhang, Zhirou Zhang, Sheng Xu, Xuyue Yang
Summary: This study prepared a dilute Mg-0.8 wt% Nd alloy through hot compression to regulate microstructure and texture, aiming to overcome the trade-off between stretch formability and heat resistance. Tests showed that this alloy successfully overcame the trade-off, with both better stretch formability and creep resistance compared to commercial Mg alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Construction & Building Technology
Zhenming Chen, Fei Gao, Jiyue Hu, Hongjun Liang, Shitao Huang
Summary: In this study, the deformations of giant CFST columns in a super-high-rise under-construction building were monitored for more than 400 days. The strains measured in the laboratory and on-site showed a consistent changing trend over time, which could be used for model verification. By incorporating reduction factors in the calculation of shrinkage strains and considering the stress history and redistribution in the calculation of creep strains, the modified model could accurately predict the shrinkage and creep strains of CFST columns in actual projects.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Chemistry, Physical
Stephen Okhiai Emokpaire, Nan Wang, Jide Liu, Chongwei Zhu, Xinguang Wang, Jinguo Li, Yizhou Zhou
Summary: This study investigates the effect of Ru element on the γ'-phase evolution and deformation mechanism in a fourth-generation Ni-based single-crystal superalloy. The results show that Ru element alters the distribution coefficient of other elements in the alloy, leading to a difference in microstructure compared to the alloy without Ru. Ru addition triggers the incubation period before primary creep stage and inhibits the slip system {111}<112> at medium-temperature and high-stress creep, resulting in a considerably low creep rate and high creep life for the Ru-containing alloy.
Article
Materials Science, Multidisciplinary
Kumar Sourabh, J. B. Singh
Summary: The creep behavior of Ni-base superalloy 690 was studied under constant load creep conditions at temperatures ranging from 800 to 1000 ℃ and stresses ranging from 25 to 105 MPa. The alloy exhibited power-law creep behavior and followed the Monkman-Grant relationship. The majority of creep data points fell within a +/- 5% scatter band on the Larson Miller parameter vs. log stress plot. The alloy underwent more than 50% of its life in the tertiary creep regime and predominantly failed due to cavitation. The apparent activation energy and stress exponent of creep were relatively high.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
Zhen Xu, Zhiwei Lv, Chuan Guo, Yang Zhou, Gan Li, Xiaogang Hu, Xinggang Li, Qiang Zhu
Summary: The steady-state creep mechanisms of a superlattice gamma'-strengthened Co-Al-W-Ta-Ti single crystal superalloy were studied under different temperature and stress conditions. The microstructures of the creep samples varied significantly according to the experimental conditions. Lomer-Cottrell locks and stacking faults interactions dominated the low-temperature and high-stress creep regime, while dislocations cross-slip and dislocation tangles contributed to the main creep resistance at intermediate temperatures and moderate stresses. The interactions of stacking faults and dislocation networks were the strengthening mechanism for the high-temperature and low-stress creep regime. The steady-state creep rate followed a classical power law equation, with a calculated creep activation energy of 378.46 kJ/mol. These findings provide insights into the effects of temperature and stress on steady-state creep mechanisms, and highlight the potential of the gamma'-strengthened Co-Al-W-Ta-Ti single crystal superalloy as a high-temperature structural material.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Petr Kral, Jiri Dvorak, Vaclav Sklenicka, Zenji Horita, Yoichi Takizawa, Yongpeng Tang, Lenka Kuncicka, Marie Kvapilova, Marie Ohankova
Summary: High-pressure sliding (HPS) and rotary swaging (RS) were used to form severely deformed microstructures in martensitic creep-resistant P92 steel. Analysis showed that HPS-processed P92 steel exhibited higher creep strength and ductility compared to RS-processed P92 steel at 500 degrees C, but with lower stress exponent values. At stresses lower than 500 MPa, the creep resistance of RS-processed state was higher than the HPS-processed state.
Article
Materials Science, Paper & Wood
Hakimeh Koochi, Jonatan Mac Intyre, Leevi Viitanen, Antti Puisto, Nahid Maleki-Jirsaraei, Mikko Alava
Summary: The aging behavior of TEMPO-CNF suspensions, which are fundamentally different from low-density gels, is investigated using rheological measurements and experiments. The aging effect is found to result in the logarithmic growth of the elastic modulus and a decrease in particle velocity. Based on experimental evidence, it is proposed that the aging effect in TEMPO-CNFs occurs due to the restructuring of fibrous elements and does not develop homogeneously across the whole sample.
Article
Materials Science, Paper & Wood
Isaac Y. Miranda-Valdez, Sebastian Coffeng, Yu Zhou, Leevi Viitanen, Xiang Hu, Luisa Jannuzzi, Antti Puisto, Mauri A. Kostiainen, Tero Makinen, Juha Koivisto, Mikko J. Alava
Summary: Foam-formed cellulose biocomposites with added organosolv lignin enhance the properties required for applications such as insulation, packaging, and cushioning. The addition of lignin increases Young's modulus, protects against bacterial growth, and improves surface hydrophobicity. The optimization of the foam composition offers a potential path for industrial-scale development.
Article
Engineering, Electrical & Electronic
Elias Paakkunainen, Lasse Laurson, Paavo Rasilo
Summary: We propose a new approach to model high-frequency losses in transverse anisotropy magnetic tapes by solving a 1-D eddy-current problem coupled to a micromagnetic constitutive law. Unlike previous models, this model is derived using a magnetic flux density conforming formulation. It allows coupling the tape-level magnetization process to a 2-D finite element model for analyzing larger cores. The model shows good agreement with previously presented measured results and models, demonstrating potential for increased accuracy in calculating losses in tape-wound cores.
IEEE TRANSACTIONS ON MAGNETICS
(2023)
Article
Materials Science, Paper & Wood
Leevi Viitanen, Isaac Y. Miranda-Valdez, Juha Koivisto, Antti Puisto, Mikko Alava
Summary: A more sustainable future requires bio-based alternatives to replace plastic foams for various applications. Research has shown that bio-based foams, fabricated using liquid foam templating and methyl cellulose as main constituents, have potential in packaging, insulation, and cushioning. However, scaling up production requires a comprehensive understanding of the foam's rheology during shaping and drying processes.
Article
Instruments & Instrumentation
K. Mulewska, F. Rovaris, F. J. Dominguez-Gutierrez, W. Y. Huo, D. Kalita, I. Jozwik, S. Papanikolaou, M. J. Alava, L. Kurpaska, J. Jagielski
Summary: In this study, multi-scale numerical modeling was used to investigate the nanomechanical response of pristine and ion-irradiated high purity iron specimens. The sudden displacement burst observed in the load-displacement curves during loading was found to be connected with increased shear stress due to dislocation slip activation and mobilization by ion irradiation. Molecular dynamics and 3D-discrete dislocation dynamics simulations provided insights into the nucleation mechanisms of geometrically necessary dislocations and their qualitative agreement with GNDs density mapping images. It was also observed that the nucleated dislocations and defects were responsible for the increase in material hardness, as evidenced by the recorded load-displacement curves and pop-ins analysis.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2023)
Article
Materials Science, Multidisciplinary
Kamran Karimi, Mikko J. Alava, Stefanos Papanikolaou
Summary: We investigated the behavior of the local, microstructural elastic modulus across the plastic yielding transition in six Ni-based multicomponent glasses. Elastic modulus fluctuations displayed consistent percolation characteristics, indicating universal behavior across chemical compositions and overall yielding sharpness characteristics. Elastic heterogeneity grew upon shearing via the percolation of elastically soft clusters within an otherwise rigid amorphous matrix, confirming prior investigations in granular media and colloidal glasses. We observed clear signatures of percolation transition with spanning clusters that were universally characterized by scale-free characteristics and critical scaling exponents.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
F. J. Dominguez-Gutierrez, P. Grigorev, A. Naghdi, J. Byggmastar, G. Y. Wei, T. D. Swinburne, S. Papanikolaou, M. J. Alava
Summary: In this study, molecular dynamics simulations were used to emulate spherical nanoindentation experiments on crystalline W matrices at different temperatures and loading rates. Different approaches were employed and compared, including traditional potentials and a machine-learned tabulated Gaussian approximation potential (tabGAP). The results showed similarities in load-displacement curves and dislocation densities at low and room temperature, but significant differences in the early stages of elastic-to-plastic deformation transition, indicating different mechanisms for dislocation nucleation and dynamics.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
R. Alvarez-Donado, S. Papanikolaou, A. Esfandiarpour, M. J. Alava
Summary: High entropy alloys (HEAs) are multicomponent crystals with excellent physical properties that violate traditional thermodynamic rules. We use molecular simulations and rapid cooling protocols to investigate seven CSSs, determine their structural features and configurational entropy, and find that the entropic rule of mixing is not always accurate for predicting alloy formation. We propose a Kauzmann-like model to relate the order-disorder transition temperature T-OD of CSSs with their single-phase stability.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Suvi Santa-aho, Mari Honkanen, Sami Kaappa, Lucio Azzari, Andrey Saren, Kari Ullakko, Lasse Laurson, Minnamari Vippola
Summary: This study thoroughly characterized two types of steels, ferrite and ferrite-pearlite, using multi-instrumental microscopy techniques to obtain detailed information about their microstructure and magnetic structure. The researchers observed the motion of magnetic domain walls and their interactions with different pinning sites, which provided explanations for changes in sample magnetization. The findings have significant implications for the non-destructive Barkhausen noise technique.
MATERIALS & DESIGN
(2023)
Article
Mechanics
H. Koochi, Jonatan Mac Intyre, M. Korhonen, A. Puisto, N. Maleki-Jirsaraei, M. J. Alava
Summary: The impact of thixotropy on the settling behavior of a solid sphere is studied using a finite element-computational fluid dynamics simulation. The flow behavior is evaluated by coupling the Navier-Stokes equations with the dynamic evolution of an initially heterogeneous fluid's microstructure. The study identifies different settling regimes based on the degree of structuring, associated heterogeneity, local morphology of the microstructure, and stress induced by the sphere. The results show that the competition between orthokinetic and perikinetic build-up and shear-induced break-down of the microstructure plays a vital role in understanding the connection between flow curve and settling behavior of the fluids.
Article
Physics, Applied
Mahshid Pournajar, Tero Maekinen, Seyyed Ahmad Hosseini, Paolo Moretti, Mikko Alava, Michael Zaiser
Summary: The failure patterns of quasibrittle materials with self-similar hierarchical microstructures are different from the standard scenario of damage accumulation and crack growth. This study investigates the failure of paper sheets with hierarchical slice patterns, nonhierarchical samples, and unpatterned reference samples under tensile loading and creep conditions. The results show that hierarchical patterning effectively mitigates strain localization and crack propagation, leading to increased residual strength for cracked samples and unusual behavior in creep curves.
PHYSICAL REVIEW APPLIED
(2023)
Article
Materials Science, Multidisciplinary
Amir H. Naghdi, Kamran Karimi, Axel E. Poisvert, Amin Esfandiarpour, Rene Alvarez, Pawel Sobkowicz, Mikko Alava, Stefanos Papanikolaou
Summary: Recent experiments and atomistic simulations have shown that equiatomic NiCoCr solid solutions exhibit exceptional mechanical properties that may be linked to nanostructural short-range order (SRO) arising from thermal treatments. This study uses hybrid Monte Carlo-molecular dynamics simulations to further understand the thermal effects on SRO formation and edge dislocation plasticity mechanisms in equiatomic NiCoCr solid solutions. The results suggest that the presence of SROs enhances the roughening mechanism and leads to significant improvements in dislocation glide resistance, ultimately improving alloy strength through the interplay between nanoscopic SROs and atomic-level misfit properties.
Article
Physics, Multidisciplinary
Sami Kaappa, Lasse Laurson
Summary: Barkhausen noise in disordered ferromagnets is primarily caused by the irregular movement of domain walls. Through micromagnetic simulations, we study the magnetization reversal process in disordered permalloy thin films and find that it involves the gradual formation of immobile 360 degrees domain walls through a sequence of localized magnetization rotation events. The density of these domain walls and the statistical properties of Barkhausen jumps are influenced by the strength of disorder.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Chemistry, Applied
Isaac Y. Miranda-Valdez, Jesus G. Puente-Cordova, Flor Y. Renteria-Baltierrez, Lukas Fliri, Michael Hummel, Antti Puisto, Juha Koivisto, Mikko J. Alava
Summary: This paper explores the potential of using fractional calculus models to describe the viscoelastic properties of soft solids, focusing on methylcellulose aqueous systems. The results show that fractional calculus can accurately describe the rheological behavior of methylcellulose, particularly the frequency- and temperature-dependent rheology. Additionally, the study showcases how the use of one springpot can replace multiple spring-dashpot arrangements, simplifying the model. Lastly, the study finds that the thermogelation of methylcellulose involves the cooperative mobility of polymer chains and can be compared to the glass transition in polymers.
FOOD HYDROCOLLOIDS
(2024)
Article
Energy & Fuels
Isaac Y. Miranda-Valdez, Maryam Roza Yazdani, Tero Makinen, Sebastian Coffeng, Leevi Viitanen, Juha Koivisto, Mikko J. Alava
Summary: This study demonstrates that cellulose foams can exhibit solid-liquid phase change functionality by adding a phase change material during the foam forming process. The resulting cellulose phase change foams have low density, high Young's modulus, and excellent dimensional stability and thermal absorption capacity at specific temperatures. This opens up broad applications for the cellulose phase change foams as thermal insulators.
JOURNAL OF ENERGY STORAGE
(2023)
