Article
Engineering, Mechanical
Y. Z. Li, Z. Y. Liang, M. X. Huang
Summary: This study investigates the effect of warm rolling on the deformation mechanisms of TWIP steel. It is found that while dislocation multiplication always controls the maximum flow stress, deformation twinning becomes increasingly important for steels with larger warm rolling reductions. The twinning kinetics is enhanced by the high dislocation densities caused by warm rolling, leading to an enhancement of twinning-induced hardening.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Engineering, Mechanical
Xiangru Guo, Chaoyang Sun, Chunhui Wang, Jun Jiang, M. W. Fu
Summary: Deformation twins play a crucial role in the plastic deformation of TWIP steels by affecting dislocation movement. A proposed dislocation-TB interaction model helps understand the strengthening effects of twins on macro deformation behaviors and dislocation reactions in TWIP steel micropillar. This research enhances the knowledge of dislocation-TB interaction mechanisms in plastic deformation of TWIP steels.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Materials Science, Multidisciplinary
Xiangru Guo, Ningdong Mao, Chaoyang Sun, Chunhui Wang, Yinan Cui, Zhiping Xiong
Summary: In this study, the tension-compression asymmetry and orientation effect of dislocation-twin boundary interactions in twinned TWIP steel were investigated using discrete dislocation dynamics simulations and Schmid's law. The research advances the understanding of the asymmetric behavior of twinning and its influence on the macro hardening in plastic deformation of TWIP steels.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Juan Macchi, Steve Gaudez, Guillaume Geandier, Julien Teixeira, Sabine Denis, Frederic Bonnet, Sebastien Y. P. Allain
Summary: The evolution of dislocation densities in martensite and austenite during the quench process of a low-carbon steel was investigated. The study found that dislocation density increases as the transformation proceeds in both martensite and austenite, indicating a heterogeneous microstructure in lath martensite and the hard nature of austenite. This contradicts recent theories attributing a major role in martensite plasticity to films of retained austenite.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Manufacturing
Charles R. Fisher, Kelly E. Nygren, Armand J. Beaudoin
Summary: The shipbuilding industry is focusing on developing digital twin technology, but the lack of material processing data in simulations affects the accuracy of structural performance. Integrated Computational Materials Engineering (ICME) techniques link digital information across multiple length scales to reduce the time and cost of physical testing needed for validation. This study validates the materials-informed digital twin method through physical specimen selection, finite-element analysis (FEA) based welding simulations, and comparison of predicted strain data with experimental results using energy dispersive diffraction (EDD) techniques.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Materials Science, Multidisciplinary
Zigan Xu, Jiyao Li, Xiao Shen, Tarek Allam, Silvia Richter, Wenwen Song, Wolfgang Bleck
Summary: This study demonstrates the relationship among processing, microstructure, and mechanical properties of a warm-rolled medium-Mn steel containing 1.5 wt. % Cu and 1.5 wt. % Ni. The warm-rolled specimen exhibited comparable tensile properties with a significantly shortened process route compared to traditional routes. The warm-rolling process shows promise for its excellent tensile properties and compact processing route in medium-Mn steel development.
Article
Nanoscience & Nanotechnology
Wang Cai, Chunhui Wang, Chaoyang Sun, Lingyun Qian, M. W. Fu
Summary: This study investigated the microstructure evolution and fracture behaviors of TWIP steel at different strain rates, revealing the competition between twinning and dislocation slip, as well as the dynamic mechanical properties of TWIP steel at high strain rates.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Metallurgy & Metallurgical Engineering
Janaina Rosa de Lima, Guilherme Oliveira Siqueira, Ernesto Soares Freitas Neto, Fabio Nakagomi, Dagoberto Brandao Santos, Reny Angela Renzetti
Summary: This study investigates the effects of thermal treatment and cold rolling on the microstructure and hardness of Fe-24Mn-3Al-1Ni-2Si-0.06C alloy. High-resolution X-ray diffraction technique and diffraction method are used for analysis and calculation. The results show that cold rolling increases hardness and induces deformation twins, stacking fault, and dislocation to different degrees. Annealing affects X-ray diffraction parameters such as stacking fault probability and dislocation density.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Chemistry, Physical
Tianhang Yu, Yu Su, Jun Li, Huaqing Fu, Zhouxiang Si, Xiaopei Liu
Summary: This study investigated the stress-strain behavior and microstructural changes of Fe-Mn-Si-C twin-induced plasticity (TWIP) steel cylindrical components at different depths of deep drawing and after deep drawing deformation at various positions. The research revealed that the extent of grain deformation and structural defects gradually increased with increasing drawing depth. Different predominant textures were observed at different positions of the cylinder components.
Article
Materials Science, Multidisciplinary
Ivan Ivanov, Jose Julio Gutierrez Moreno, Kemal Emurlaev, Daria Lazurenko, Ivan Bataev
Summary: It is commonly believed that the dislocation density decreases during recovery in cold-worked metals. However, this study used in-situ synchrotron X-ray diffraction and classical molecular dynamics simulation to show that the dislocation density in β-titanium actually increases at the initial stages of heating. The findings suggest that the generation of new dislocations can reduce overall stresses and potential energy during heating of deformed materials under conditions of low dislocation mobility.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
T. W. J. Kwok, T. P. McAuliffe, A. K. Ackerman, B. H. Savitzky, M. Danaie, C. Ophus, D. Dye
Summary: A TWIP steel with a specific composition was deformed to 6% strain and analyzed using 4D-STEM technique. It was found that the average elastic strain parallel and perpendicular to the twinning direction was about 6%, but there were hot spots with even larger strains up to 12%. These hot spots were attributed to a high density of Frank dislocations on the twin boundary. The strain fields in the TWIP steel were significantly larger than other twinning materials, and could explain the early thickness saturation of nanotwins.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Imed-Eddine Benrabah, Frederic Bonnet, Benoit Denand, Alexis Deschamps, Guillaume Geandier, Hugo P. Van Landeghem
Summary: Knowledge of phase transformation kinetics is crucial in designing steel grades, and a high-throughput approach has been developed to overcome traditional limitations, accelerating the design of low-alloy steel grades. The study of transformation mechanisms revealed the impact of solute drag on mobile interfaces.
APPLIED MATERIALS TODAY
(2021)
Article
Materials Science, Multidisciplinary
Hans-Henrik Konig, Niklas Hollander Pettersson, A. Durga, Steven Van Petegem, Daniel Grolimund, Andrew Chihpin Chuang, Qilin Guo, Lianyi Chen, Christos Oikonomou, Fan Zhang, Greta Lindwall
Summary: This study investigates the impact of solidification velocities and thermal gradients on the solidification mode of a hot-work tool steel during additive manufacturing (AM) using high-speed X-ray diffraction measurements. The results show that primary delta-ferrite forms at a cooling rate of 2.12 x 104 K/s, while it is suppressed at a higher cooling rate of 1.5 x 106 K/s and primary austenite is observed. A Kurz-Giovanola-Trivedi (KGT) based solidification model is used to validate the experimental findings. This work emphasizes the importance of in situ XRD measurements for understanding microstructure evolution and validating computational models in AM processes.
Article
Nanoscience & Nanotechnology
Jiahua Yuan, Minghao Huang, Yizhuang Li, Lingyu Wang, Huabing Li, Wei Xu
Summary: Twinning-induced plasticity (TWIP)-assisted steel shows potential in engineering applications due to its strength and ductility. The dominant strengthening mechanism of TWIP-assisted steels is still unclear, with debate over the contributions of dislocations and deformation twinning. By preparing samples with different grain sizes, it was found that twinning-induced strengthening is grain size-dependent. Dislocation slip dominates plasticity in small grain sizes, while single-oriented twinning and multi-oriented twinning occur with increasing grain sizes. The strengthening effect is enhanced by the interaction between deformation twins and dislocations in multi-oriented twin variants.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Mechanical
Sam Oliver, Chris Simpson, David M. Collins, Christina Reinhard, Martyn Pavier, Mahmoud Mostafavi
Summary: Thermal shock is crucial in the operation of pressure vessels, affecting their structural integrity. Experiments and numerical simulations are used to evaluate the effects of thermal shock and study the transient material response. Research demonstrates that peak stress intensity occurs during thermal shock, rather than under steady conditions before or after.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Nanoscience & Nanotechnology
Y. Ngiam, Z. H. Cao, M. X. Huang
Summary: This study develops a combined model that couples the phase field model and a modified hydrogen diffusion model to investigate the relationship between hydrogen diffusion and hydrogen embrittlement in martensitic press-hardened steel (PHS). Experimental and simulation results demonstrate that defects in the martensitic microstructure, such as lath boundaries (LB) and prior-austenite grain boundaries (PAGB), are the preferred locations for hydrogen storage, and these boundaries are prone to hydrogen embrittlement when the material's hydrogen concentration reaches a critical value.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
S. Pan, X. K. Shang, B. B. He, M. X. Huang
Summary: Annealing treatment is commonly used to recover the ductility of high/medium entropy alloys, but this study shows that the ductility of a CoCrNiVC medium entropy alloy can be substantially reduced after the tempering process, similar to tempering embrittlement in some steels. Numerous chromium-enriched carbides are formed at shear bands and grain boundaries during tempering, leading to localized strain concentration during plastic deformation and facilitating the nucleation of micro-cracks. The segregation of carbon at grain boundaries decreases cohesion energy, accelerating crack propagation and intergranular fracture development.
Article
Materials Science, Multidisciplinary
C. Hu, C. P. Huang, Y. X. Liu, A. Perlade, K. Y. Zhu, M. X. Huang
Summary: In this study, the tensile and fracture behaviors of a medium Mn steel fabricated by intercritical annealing (IA) and room-temperature quenching and partitioning (RT Q&P) processes were investigated. The IA steel consists of ultrafine-grained ferrite and austenite, while the RT Q&P steel is comprised of martensite matrix and retained austenite. The strain localization is moderate in the RT Q&P steel but highly localized in the IA steel, leading to premature decohesion and sudden fracture.
Article
Engineering, Mechanical
H. Liu, X. K. Shang, B. B. He, Z. Y. Liang
Summary: The strain rate sensitivity of lath martensite and its underlying physics were investigated, revealing that strain rate has minor effect on mechanical properties at low strain rates and that both yield strength and work-hardening rate significantly increase at high strain rates. Microstructural characterization showed that the enhanced yield strength during high-strain-rate deformation is due to larger lattice friction for dislocation slip, and the higher work-hardening rate is attributed to the increased strain gradient resulting in the generation of geometrically-necessary dislocations.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Review
Metallurgy & Metallurgical Engineering
Zuoheng Cao, Zhou Wang, Yan Ngiam, Zhichao Luo, Zhiyu Geng, Jingjing Wang, Yu Zhang, Mingxin Huang
Summary: The application of press-hardened steels (PHSs) in automotive body-in-white components using the hot-stamping technique is growing. However, the issue of hydrogen embrittlement (HE) hinders the rising trend of PHSs application by causing mechanical property degradation. This study highlights techniques to characterize the hydrogen content and distribution, techniques to evaluate HE susceptibility, and potential models to simulate the in-service performance of PHS. Future studies are expected to establish a conclusive HE evaluation standard for PHS based on the review of existing studies.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Cuncai Fan, Shijun Zhao, Shuai Pan, Binbin He, Mingxin Huang
Summary: Understanding the effects of ion channeling on helium radiation blistering is crucial for developing advanced plasma-facing materials. In this study, we used a Helium Ion Microscope to investigate the behavior of helium ions implanted into tungsten grains. The results showed that channeling and non-channeling grains exhibited different blistering behaviors, with the non-channeling grains having smaller and shallower blisters with more and larger cracks beneath the surface. Molecular Dynamic simulations were used to discuss the underlying mechanisms, providing insights for designing plasma-resistant materials through texture and anisotropy tailoring.
Article
Materials Science, Multidisciplinary
Cuncai Fan, Shuai Pan, Xunxiang Hu, Binbin He, Mingxin Huang
Summary: The present study presents a systematic investigation of helium irradiation blistering on tungsten surfaces with different orientations ({100}, {110}, and {111}). The results reveal that the blistering deformation starts with nanocrack nucleation at the peak in the bubble depth distribution, followed by gas buildup in a primary cavity. The study also shows that the blistering behaviors vary between different orientations of tungsten surfaces.
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
Engineering, Mechanical
Lang Liu, Liejun Li, Zhiyuan Liang, Mingxin Huang, Zhengwu Peng, Jixiang Gao, Zhichao Luo
Summary: A medium-Mn dual-phase steel was proposed to develop a strong and damage-resistant steel by refining the microstructure. The experimental results showed that the developed steel exhibited outstanding ultimate tensile strength and high elongation when the martensite volume fraction was 55%. However, as the martensite volume fraction increased, the fracture strain decreased significantly, and the necking behavior transitioned. It is suggested to choose a moderate martensite volume fraction range when developing a 1470 MPa grade dual-phase steel with excellent damage tolerance.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Nanoscience & Nanotechnology
M. Guana, Y. Wanga, Y. X. Liua, Z. Wangc, M. X. Huang
Summary: The present study demonstrates that a new heat treatment process involving double austenitization can optimize the coating structure and prior austenite grain size (PAGS) of AlSi-coated 2GPa-grade press hardened steel (PHS), resulting in improved bendability while maintaining similar ultimate tensile strength (UTS). The interdiffusion ferrite layer in the coating structure is found to be responsible for the improved bendability, while the controlled PAGS ensures similar UTS. By employing a double austenitization process, an interdiffusion ferrite layer with an Al content lower than 4 wt.% is produced, leading to a bending angle improvement of over 60 degrees while retaining similar UTS.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Hui Liu, Jinzhi Li, Binbin He, Zhiyuan Liang
Summary: This study explores the potential of using medium Mn steel for hot/warm forming to achieve excellent strength-ductility combination. By processing at specific temperatures, a duplex microstructure consisting of ferrite with high dislocation density and retained austenite is formed, resulting in outstanding mechanical properties. Compared to the commonly used 22MnB5 boron steel, the medium Mn steel exhibits higher energy absorption capacity.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Nanoscience & Nanotechnology
H. Jiang, K. P. Yu, X. C. Liu, L. H. He, B. B. He, M. X. Huang
Summary: This paper introduces a new type of compositionally complex oxide (CCO) with a spinel structure embedded in a new body-centered cubic compositionally complex alloy (CCA) matrix. The crystal structure of the new CCO, characterized by neutron diffraction and high-resolution transmission electron microscopy, shows that Mn atoms occupy the tetrahedral position while V, Ti, and Al atoms share the octahedral sites. The combination of the new CCO with the new CCA matrix demonstrates a potential strategy for developing new oxide-metal composites.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
L. K. Huang, F. Liu, M. X. Huang
Summary: The bainite transformation in medium Mn steels has been experimentally and theoretically studied, and it has been found that the transformation kinetics is slow. However, the introduction of dislocations can significantly accelerate the transformation rate. A new "carbon depletion mechanism" is proposed to explain the role of dislocations in the acceleration of bainite transformation, and a physical model is developed to quantitatively understand the kinetics of bainite transformation.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2024)
Review
Materials Science, Multidisciplinary
Chengpeng Huang, Chen Hu, Yuxuan Liu, Zhiyuan Liang, Mingxin Huang
Summary: This article provides a systematic review of the state-of-the-art developments of medium Mn steel, focusing on alloy design, thermomechanical processing, fracture mechanisms, and hydrogen embrittlement.
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.
