Article
Engineering, Manufacturing
Yachao Wang, M. Minhaj, Xinnan Wang, Jing Shi
Summary: This research explores the deformation behaviors of monocrystalline and polycrystalline silicon materials in nanoindentation using atomistic simulation approach. The study validates the molecular dynamics simulation model for nanoindentation, reveals intriguing phenomena like phase transformation and grain size effects, and observes an inverse Hall-Petch effect in the nanoindentation process of silicon.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Materials Science, Multidisciplinary
F. H. Duan, Y. Naunheim, C. A. Schuh, Y. Li
Summary: The study investigates the hardness and deformation behavior of body centered cubic Mo(O) alloys with grain sizes ranging from 120 to 4 nm, highlighting a peak hardness at 11 nm and a transition towards glass-like deformation behaviors as grain size decreases.
Article
Metallurgy & Metallurgical Engineering
Hiroyuki Yasuda, Ken Cho, Yohei Murozumi, Masanobu Nomoto, Hiroki Toda, Wataru Suzuki
Summary: Hall-Petch slopes of Fe-based alloys were measured by nanoindentation tests, and the pop-in phenomenon associated with slip transfer across grain boundaries was observed. The Hall-Petch slope depended on the alloying element and its segregation at grain boundaries, as well as the type of grain boundary and the combination of activated slip systems in neighboring grains.
TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN
(2022)
Article
Materials Science, Multidisciplinary
Mohsen Taheri Andani, Aaditya Lakshmanan, Veera Sundararaghavan, John Allison, Amit Misra
Summary: This study investigates the micro-Hall-Petch coefficient values for prismatic slip in Mg-4Al alloys and their correlation with grain boundary parameters. The results show that the k(mu)(pr)(ismat)(ic) values vary significantly among different grain boundaries and are larger than the values for basal micro-Hall-Petch. A functional relationship based on two effective angles is proposed to estimate the Hall-Petch barrier for prismatic slip system.
Article
Nanoscience & Nanotechnology
Qibin Wang, Qi Wang, Ruirun Chen, Xiaowei Wang, Yanqing Su, Hengzhi Fu
Summary: The microstructural evolution and flow softening behavior of Nb-24Ti-16Si-2Al-4Fe-5V alloy during hot deformation under different processing parameters were studied. The as-cast Nbss/beta-(Nb, X)5Si3 eutectic structure transformed into the Nbss matrix and beta-(Nb, X)5Si3 blocks with fine recrystallized grains after hot deformation. The refinement mechanism of the beta-(Nb, X)5Si3 phase involved silicide splitting and continuous dynamic recrystallization (CDRX). The flow softening behavior of the alloy was mainly influenced by the CDRX behavior of the Nbss phase, with recrystallization refinement improving the hardness (H) of the Nbss phase.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Mechanics
Fan Yang, Yanhui Wu, Zhiyang Chen, Stephen Spence, Bo Li
Summary: The study investigates the unsteadiness caused by tip leakage vortex breakdown and identifies the role of the back flow vortex in rotating instability. Experimental tests and numerical simulations reveal high-frequency and low-frequency unsteady flow structures.
Article
Multidisciplinary Sciences
Xin Lou, Qing Yang, Yu Ding, Peng Liu, Ke Chen, Xin Zhou, Fangfu Ye, Rudolf Podgornik, Mingcheng Yang
Summary: Broken time-reversal and parity symmetries in active spinner fluids lead to a nondissipative odd viscosity, resulting in phenomena not achievable in traditional passive or active fluids. Our study demonstrates that the odd viscosity itself can cause a Hall-like transport when the active chiral fluid flows through a quenched matrix of obstacles, resembling an anomalous Hall effect. The Hall-like velocity depends on spinner activity and longitudinal flow due to the interplay between odd viscosity and spinner-obstacle collisions.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Physics, Applied
L. A. Boatner, C. B. Finch, W. E. Brundage, J. A. Kolopus, G. R. Gruzalski, K. E. Johanns, P. Sudharshan Phani, G. M. Pharr, W. C. Oliver
Summary: Instrumented indentation experiments at elevated temperatures require careful attention to experimental details, including the choice of indenter tip material. This study used rf-induction heating float-zone and high-temperature solution single-crystal growth techniques to prepare a suite of bulk refractory carbide specimens. These materials were characterized and compared to sapphire and polycrystalline WC-Co, and the results showed that single-crystal WC is a promising candidate for elevated-temperature nanoindentation tips.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Mechanics
Tongjing Liu, Derong Xu, Wei Lian, Wanli Kang, Bauyrzhan Sarsenbekuly
Summary: This study proposes the use of micro-emulsification to reduce the viscosity of heavy oil for enhanced oil recovery. The optimal injection parameters were determined through experimental tests, and the displacement mechanism of the microemulsion was revealed. The results show that the micro-emulsification technology can significantly improve the oil recovery efficiency of heavy oil.
Article
Environmental Sciences
Kumar Chandrasekaran, Alex Stanley Raja Thaveedhu, Premkumar Manoharan, Vijayarajan Periyasamy
Summary: In this study, an improved variant of the Mountain Gazelle Optimizer (AMGO(IB3H)) is proposed to solve the problem of photovoltaic model parameter extraction. This method improves the convergence of MGO and the design of objective functions, and effectively identifies the unknown parameters of the three-diode PV model using actual measured laboratory data.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Yeojin Kang, Wonjung Park, Mao Zhang, Dayoung Yoo, Dongyun Lee
Summary: In this study, the mechanical properties of CIGS compound semiconductors were investigated using different indenters. The cube-corner and conical indenter showed lower load at the same depth compared to the Berkovich indenter, resulting in smaller projected contact areas. These factors could affect the values of the mechanical properties of the thin film. Additionally, the microstructure of the CIGS thin film and the characteristics of the Mo substrate had significant effects on its mechanical properties.
KOREAN JOURNAL OF METALS AND MATERIALS
(2022)
Article
Engineering, Multidisciplinary
Alexandre M. Barboza, Luis C. R. Aliaga, Ivan N. Bastos
Summary: This study investigates the mechanical behavior of nanocrystalline aluminum, focusing on deformation mechanisms using molecular dynamics simulations. Four nanocrystalline samples with varying grain sizes were created and subjected to tensile tests. The results showed an inverse Hall-Petch relationship and negligible improvement in mechanical strength. Dislocation analysis revealed a decrease in perfect dislocation density and an increase in Shockley partials during testing. Grain boundary-mediated plasticity was observed through atomic diffusion and grain rotation. This suggests that conventional plastic deformation mechanisms are not dominant in nanocrystalline aluminum.
INGENIERIA E INVESTIGACION
(2023)
Article
Chemistry, Physical
Jungmoo Han, Uihwan Jeong, Youngseo Lee, Karuppasamy Pandian Marimuthu, Hyungyil Lee
Summary: The mechanical behavior of Zr55Cu30Ag15 bulk metallic glass was studied using the free volume theory, with experiments and finite element models showing the advantages of the implemented model. Two key model parameters were identified through sensitivity studies, highlighting the effectiveness of the pressure-dependent free volume model in describing load-depth responses and shear band behavior in nanoindentation tests.
Article
Nutrition & Dietetics
Jahangir A. Rather, Syed Darakshan Majid, Aamir Hussain Dar, Tawheed Amin, H. A. Makroo, Shabir Ahmad Mir, Francisco J. Barba, B. N. Dar
Summary: This study evaluated the impact of freeze-drying and hot air drying on the characteristics of chicken feet gelatin. The results showed that hot air dried gelatin had higher water activity, pH, and gel strength compared to freeze-dried gelatin. However, freeze-dried gelatin had better foaming capacity, emulsion capacity, water holding capacity, and oil binding capacity. Therefore, chicken feet gelatin can be utilized in various food products to enhance functionality and has potential for developing edible packaging materials.
FRONTIERS IN NUTRITION
(2022)
Article
Mechanics
Fanette Chassagne, Michael C. Barbour, Michael R. Levitt, Alberto Aliseda
Summary: This study aimed to evaluate the combined effects of Re, De, Wo, and the geometry of the aneurysmal sac on the haemodynamics before and after treatment with FDS. The results demonstrated the primary role of haemodynamics in the treatment of intracranial aneurysms with FDS.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Materials Science, Multidisciplinary
Benjamin Seligmann, Markus Alfreider, Michael Wurmshuber, Daniel Kiener
Summary: Microelectronic devices require material systems combining multiple layers of material for proper operation. This study investigates the internal stress states and their influence on deformation behavior in a Si-WTi-Cu material system using in situ thermomechanical cantilever bending experiments. The experiments reveal that the Cu layer undergoes partial plastic deformation during heating, which may result in failure of devices. A model incorporating plastic deformation and known residual stresses is proposed and verified by Finite Element Analysis to assess the internal stress and strain states based on in situ observation.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Dominik Steinberger, Inas Issa, Rachel Strobl, Peter J. Imrich, Daniel Kiener, Stefan Sandfeld
Summary: The lifetime and performance of engineering components are influenced by fracture processes, which start at the atomic scale and interact with defects, ultimately affecting the macroscopic behavior and fracture properties. Identifying the atomistic processes at a crack tip remains a challenge. Researchers have developed a method combining quantitative in-situ observations, three-dimensional reconstruction of dislocation structure, and computational analysis to better understand and control local failure processes.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Michael Wurmshuber, Simon Doppermann, Stefan Wurster, Severin Jakob, Mehdi Balooch, Markus Alfreider, Klemens Schmuck, Rishi Bodlos, Lorenz Romaner, Peter Hosemann, Helmut Clemens, Verena Maier-Kiener, Daniel Kiener
Summary: To improve the mechanical properties of tungsten, boron and hafnium were added to enhance the cohesion of grain boundaries. Small-scale testing techniques showed a significant improvement in the mechanical properties of tungsten after doping. Moreover, a low-temperature heat treatment of the boron-doped samples further enhanced the mechanical properties. This study provides an effective pathway for improving the mechanical properties of ultra-fine grained tungsten using grain boundary segregation engineering, enabling challenging applications in harsh environments.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2023)
Editorial Material
Chemistry, Multidisciplinary
Juergen Eckert, Daniel Kiener
Article
Materials Science, Multidisciplinary
Michael Wurmshuber, Markus Alfreider, Stefan Wurster, Michael Burtscher, Reinhard Pippan, Daniel Kiener
Summary: The brittleness of tungsten is a challenge for its application as a divertor material in nuclear fusion reactors. Grain refinement is a promising strategy to increase its fracture toughness, but it also promotes intercrystalline crack growth. This study explores the use of grain boundary doping with boron and hafnium to enhance the fracture toughness of ultrafine-grained tungsten. The results show that doping with boron and hafnium can improve the fracture toughness of ultrafine-grained tungsten, with values up to 27 MPa root m.
Article
Materials Science, Multidisciplinary
T. Kluensner, M. Krobath, R. Konetschnik, C. Tritremmel, V. Maier-Kiener, D. Samardzic, W. Ecker, C. Czettl, C. Mitterer, D. Kiener
Summary: In this study, micromechanical specimens were produced using focused ion beam milling to investigate the fracture behavior of rough substrate-coating interfaces with complex defect structure. It was found that a stable value of the maximum principal stress triggering fracture in the ceramic-ceramic interfaces was observed for inclination angles >= 45 degrees. The interface strength was determined by observing the crack path at the substrate-coating interface via scanning electron microscopy and analyzing the effectively loaded interface area values.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Markus Alfreider, Michael Meindlhumer, Tobias Ziegelwanger, Rostislav Daniel, Jozef Keckes, Daniel Kiener
Summary: Nanostructured materials play a key role in various modern applications. For instance, hard and wear-resistant metal nitride coatings are essential in industrial dry-milling processes to protect cutting tools. However, improving the dynamical properties of these nanostructured thin films is challenging due to difficulties in probing parameters of (sub-)micron layers without substrate influence. To address this issue, a novel method called micromechanical spectroscopy (mu MS) based on resonance peak measurements of a cantilever-transducer system is developed and applied to an Al0.8Cr0.2N model system. The research reveals the precipitation of cubic CrN and local Cr variations in the wurtzite-type supersaturated Al0.8Cr0.2N system after annealing at 1050 degrees C, resulting in a 63 percent increase in damping capability and a 36 percent increase in Young's modulus.
Article
Chemistry, Physical
Gloria Graf, Malina Seyffertitz, Petra Spoerk-Erdely, Helmut Clemens, Andreas Stark, Lukas Hatzenbichler, David Holec, Michael Burtscher, Daniel Kiener, Xiaobing Li, Kui Liu
Summary: In order to promote the use of intermetallic γ-TiAl based alloys in the aircraft and automotive sector, recent research has focused on the development of low-cost titanium aluminides. The addition of manganese has shown potential to replace more expensive alloying elements and improve the ductility. However, Mn-containing alloys are prone to the formation of undesired brittle phases, which can affect the ductility. This study investigated the transformation kinetics and stability range of a specific brittle phase in a low-cost Ti-42Al-5Mn alloy using experimental and computational approaches. The results provide valuable insights for the future design of low-cost γ-TiAl based alloys.
Article
Materials Science, Multidisciplinary
Alexander Jelinek, Stanislav Zak, Megan J. Cordill, Daniel Kiener, Markus Alfreider
Summary: Two-photon lithography enables the design and characterization of novel micromechanical specimens, expanding the possibilities for miniaturized technologies. This study presents a methodology for automated specimen fabrication and testing, and analyzes the influence of parameters on the essential work of fracture. The findings provide a foundation for statistical fracture evaluation in other resin materials and thin film systems.
MATERIALS & DESIGN
(2023)
Article
Nanoscience & Nanotechnology
Michael Burtscher, Markus Alfreider, Christina Kainz, Daniel Kiener
Summary: The technical potential of WCu alloys is limited by the modest fracture characteristics of the material system in its coarse-grained condition. To address this, a W-50 at.% Cu composite with a nanocrystalline microstructure was processed using high-pressure torsion deformation. The resulting microstructures were quantified, and the mechanical properties were investigated. The study found that the processed specimens had smaller grain sizes and increased amount of mechanically intermixed W in the Cu grains. The mechanical properties of the processed specimens were comparable to those of the coarse-grained specimens.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Metallurgy & Metallurgical Engineering
Gloria Graf, Petra Spoerk-Erdely, Emad Maawad, Michael Burtscher, Daniel Kiener, Helmut Clemens, Thomas Klein
Summary: In recent years, wire-arc directed energy deposition (waDED), also known as wire-arc additive manufacturing (WAAM), has emerged as a promising fabrication technique for magnesium alloys. This study focuses on the aging response of a WAAM AZ91 alloy and reveals that lower temperature aging is preferable within the investigated range of 250-325°C. Additionally, no significant difference is found between directly aged and conventionally aged samples.
JOURNAL OF MAGNESIUM AND ALLOYS
(2023)
Article
Nuclear Science & Technology
Alexander J. Leide, Thomas A. Haynes, Nassia Tzelepi, John Payne, Matthew Jordan, Steven Knol, Jan A. Vreeling, Mark Davies, David T. Goddard, Manuel J. Pfeifenberger, Markus Alfreider, Daniel Kiener, Dong Liu
Summary: This study applies FIB-DIC analysis to evaluate the residual stresses in coated fuel particles, specifically in the pyrolytic carbon and silicon carbide layers. The findings indicate the existence of tensile residual hoop stresses in the pyrolytic carbon layers and compressive residual hoop stress in the silicon carbide layer. These stresses, which were not accounted for in previous models, are comparable to the stresses predicted in real fuel particles.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Materials Science, Multidisciplinary
Daniel Kiener, Amit Misra
Summary: This article provides an overview of recent developments in test methodologies for nanoindenter-based small-length-scale mechanical characterization. It emphasizes the possibilities offered by in situ testing in transmission and scanning electron microscopes, as well as the examination of strain rate and temperature dependence of mechanical strength. The versatility and growing impact of new nanomechanical characterization tools are highlighted through selected recent examples.
Article
Materials Science, Multidisciplinary
Lukas Schweiger, Daniel Kiener, Michael Burtscher, Erhard Schafler, Gregor Mori, Florian Spieckermann, Juergen Eckert
Summary: A bulk nanocomposite with a FeTi-Cu composition was prepared using high-pressure torsion, and satisfactory microstructural homogeneity was achieved at high temperatures due to self-reinforcement. However, processing at room temperature remained challenging.
MATERIALS TODAY ADVANCES
(2023)
Review
Materials Science, Multidisciplinary
Daniel Kiener, Michael Wurmshuber, Markus Alfreider, Gerald J. K. Schaffar, Verena Maier-Kiener
Summary: Nanoindentation techniques have been greatly improved by continuous stiffness monitoring capabilities, allowing for comprehensive characterization of hardness, elastic modulus, and plastic properties. By combining different methods and improving experimental conditions, insights into material behavior under extreme conditions can be achieved.
CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE
(2023)