Article
Chemistry, Physical
Zhibo Liu, Yaojun Lin, Zhigang Yan, Manping Liu, Xiaochun Liu, Jiani Sun, Hans J. Roven
Summary: In this study, a strategy of strengthening Al-10wt%Mg binary alloy via heavy cryogenic rolling at liquid nitrogen temperature was proposed. The combination of cryogenic plastic deformation and a high concentration of Mg solute effectively enhanced the strength and ductility of the alloy, providing a new avenue for non-age-hardened Al-Mg alloys to achieve ultrahigh strength and good ductility.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Nanoscience & Nanotechnology
Teng Tian, Min Zha, Hai-Long Jia, Zhen-Ming Hua, Pin-Kui Ma, Hui-Yuan Wang
Summary: Plastic instability caused by Portevin-Le Chatelier (PLC) known as dynamic strain aging (DSA) is a major obstacle in sheet metal forming, especially for 5000 series Al alloys. This study investigated the DSA behavior of hot extruded Al-Mg alloys with varying Mg contents and strain rates. The results showed that increasing Mg content and decreasing strain rate led to a gradual increase in the critical strain for the onset of serrated stress flow, indicating suppressed plastic instability. The type of serrations also changed with increased Mg concentrations.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Jeong-Won Choi, Weihao Li, Kohsaku Ushioda, Motomichi Yamamoto, Hidetoshi Fujii
Summary: This study investigated the effects of stacking fault energy (SFE), temperature, strain, and strain rate on microstructural evolution and dynamic recrystallization (DRX) mechanism during linear friction welding (LFW) of face-centered cubic materials, specifically Al alloys (AA1050 and AA5052). The results showed that the temperature played a crucial role in the microstructural evolution, with high temperatures leading to continuous DRX and low temperatures resulting in discontinuous DRX. The grain structure and texture evolution depended on various parameters, with strains and strain rates dominating at temperatures above 0.5Tm and the SFE influencing at temperatures below 0.5Tm. Additionally, the Zener-Hollomon parameters of the Al alloy joints were investigated, and it was found that the AA5052 joints had a larger grain diameter than the AA1050 joints at lower Z values, but a smaller grain diameter at higher Z values. These differences were attributed to the lower SFE of AA5052, which promoted DRX and grain refinement during LFW.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Engineering, Mechanical
Dengshan Zhou, Xiuzhen Zhang, Hao Wang, Yue Li, Binhan Sun, Deliang Zhang
Summary: This study investigates the influence of Mg content and dynamic strain aging (DSA) on the tensile flow behavior of Al-Mg alloys. The results show that the synergistic effect of Mg-dislocation interactions and DSA improves the strain hardening capacity of Al-Mg alloys.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Chemistry, Physical
Yifan Bu, Xiuzhen Zhang, Dengshan Zhou
Summary: Experimental observations show that the strain dependence of the Hall-Petch slope in Al-Mg alloys is significantly influenced by the formation of Laders bands and the Mg content. The Hall-Petch slope initially drops due to Laders deformation, then increases with plastic strain until reaching its maximum, and subsequently decreases due to dynamic recovery. Alloys with higher Mg contents exhibit a larger Hall-Petch slope at a given strain, and their dynamic recovery is postponed until a larger strain is reached. Interestingly, a model developed for low stacking fault energy materials accurately describes the relationship between the Hall-Petch slope, Mg content, and strain magnitude.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Xuejian Zhang, Hongwei Wang, Fengbai Ye, Chunming Zou, Zunjie Wei
Summary: This study investigates the cooperative effect of Mg and Si contents on the microstructural evolution, mechanical properties, and deformation behavior of cast Al-Li-Mg-Si alloys. It is found that increasing Mg content improves the strength and ductility of the alloys, while increasing Si content increases the amount of intergranular Si-rich phases. The study also reveals the strain partitioning behavior at the interface of Mg2Si precipitates and AlLiSi particles, and establishes a methodological framework to understand the effect of precipitates and intergranular phases on the deformation behaviors of materials.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Shiyuan Zhou, Shifeng Liu, Yuping Ding, Yahui Liu, Chao Deng, Zhiqing Zhang, Xiaoli Yuan
Summary: Dynamic plastic deformation (DPD) of tantalum was investigated using split Hopkinson pressure bar, and the microstructure of deformed samples, especially the twinning behavior, was systematically studied under various DPD conditions. It was observed that the number and distribution of {112}<111> twins were significantly affected by the deformation conditions. {110} grains were found to be more prone to twinning compared to {100} and {111} grains due to the fewer slip systems. The number of twins increased dramatically with increasing strain rate or decreasing deformation temperature. The texture of the deformed tantalum samples changed gradually from {110} to mixed {100} and {111} textures, and the number of twins initially increased and then decreased. The selection of twin variants in tantalum under DPD was found to follow Schmid law and be influenced by strain coordination. The findings of this research deepen the understanding of tantalum as a material for armor-piercing projectiles.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Lingying Ye, Xiaodong Liu, Jianguo Tang, Shengdan Liu, Yong Zhang
Summary: In an Al-Mg-Li alloy, S-1 phase precipitates in rod-shaped morphology at 300 degrees C, which are not dissolved until coarsening is finished at 400 degrees C. The dissolution of small precipitates and spheroidization of the rod-shaped precipitates reduce the total precipitate-matrix interface energy, providing the driving force for coarsening.
Article
Chemistry, Physical
Mengmeng Tong, Feng Jiang, Huiling Wang, Jingyu Jiang, Pengcheng Ye, Xuda Xu
Summary: In this study, dynamic stretching behaviors of Al-Mg-Mn-Sc-Zr alloy at various strain rates were investigated, revealing that with increasing strain rates, the alloy exhibited significant increases in peak stress and elongation, as well as improved work hardening ability. The increase in dislocation density and decrease in dislocation width enhanced resistance to dislocation movement, leading to a notable increase in peak strength. High velocity dislocations could cut through Al-3(Sc,Zr) particles, inhibiting dislocation tangle formation and promoting uniformity in dislocation distribution, ultimately improving the plasticity of the alloy during dynamic deformation.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
S. M. Hosseini, M. Roostaei, M. Mosavi Mashhadi, H. Jabbari, G. Faraji
Summary: This study used parallel tubular channel angular pressing (PTCAP) as a severe plastic deformation method to fabricate a bimetal Al/Mg tube for the first time. The results show a strong bond between layers and grain refinement after the PTCAP process. Additionally, a significant increase in hardness was observed and the diffusion rate at the interface increased with temperature.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2022)
Article
Materials Science, Multidisciplinary
Huizi Chen, Jian Wang, Xiangchen Meng, Yuming Xie, Yulong Li, Long Wan, Yongxian Huang
Summary: Utilizing friction stir processing, an ultrafine-grained structure was achieved in Mg-Zn-Y-Zr alloy leading to extraordinary superplasticity. Grain refinement and homogeneous dispersion of precipitates were promoted by the coupled thermo-mechanical effect, resulting in an ultra-fined grains size of 1.9 +/- 0.4 μm and a superplastic elongation of 642%. Grain boundary sliding was considered as the predominant superplastic deformation mechanism in ultrafine-grained materials.
Article
Metallurgy & Metallurgical Engineering
B. J. Wang, D. K. Xu, X. Q. Zhuang, L. Y. Sheng
Summary: The tensile behaviors of Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys were compared. The plastic instability of Mg-8%Li alloy was significant, while the addition of I-phase (Mg3Zn6Y) in Mg-8%Li-6%Zn-1.2%Y alloy enhanced tensile strength and eliminated plastic instability, but reduced ductility.
JOURNAL OF MAGNESIUM AND ALLOYS
(2023)
Article
Materials Science, Multidisciplinary
M. R. Gazizov, A. N. Belyakov, R. Holmestad, M. Yu. Gazizova, V. S. Krasnikov, P. A. Bezborodova, R. O. Kaibyshev
Summary: The deformation behavior of {111}Al omega plates in an Al-Cu-Mg-Ag alloy was analyzed using atomic-resolution scanning transmission electron microscopy (STEM). The transition from particle shearing to Orowan dislocation loop formation was observed at critical plate thicknesses of 3 and 3.5 cθo (2.54-2.97 nm) when considering the omega phase as consisting of the orthorhombic theta lattice (θo). For thinner plates, a full dislocation allowed particle segments to shift relative to each other in planes orthogonal to the particle habit plane. Thicker plates exhibited dislocation loops consisting of two segments with jogs, causing particle segmentation and deviation from the Al/omega orientation relationship.
Article
Chemistry, Physical
Xuanliang Chen, Minho O, Equo Kobayashi
Summary: This study applied cyclic deformation to an Al-Mg-Cu alloy and found that it increased the strength and ductility of the alloy by introducing dislocations and promoting cluster formation. The aging behaviors of the cyclically-strengthened (CS) samples were studied, and it was found that recovery and precipitation promotion occurred regardless of pre-aging. Pre-aged CS samples showed higher strength, but interestingly, after subsequent aging, the mechanical properties of pre-aged and non-pre-aged CS samples became the same.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
O. A. Yakovtseva, A. A. Kishchik, V. V. Cheverikin, A. D. Kotov, A. V. Mikhaylovskaya
Summary: High-performance aluminum-based alloys with high-strain-rate superplasticity improve the formability of lightweight constructions with complex shapes. The microstructural evolution and the contributions of deformation mechanisms were analyzed in an Al-Mg-based alloy with minor Sc and Zr additions. The results showed dynamic recrystallization and the importance of grain boundary sliding and dislocation slip/creep in the superplastic deformation process.
Article
Chemistry, Multidisciplinary
Yu Deng, Ruopeng Zhang, Thomas C. Pekin, Christoph Gammer, Jim Ciston, Peter Ercius, Colin Ophus, Karen Bustillo, Chengyu Song, Shiteng Zhao, Hua Guo, Yunlei Zhao, Hongliang Dong, Zhiqiang Chen, Andrew M. Minor
ADVANCED MATERIALS
(2020)
Article
Multidisciplinary Sciences
Ruopeng Zhang, Shiteng Zhao, Jun Ding, Yan Chong, Tao Jia, Colin Ophus, Mark Asta, Robert O. Ritchie, Andrew M. Minor
Article
Chemistry, Physical
Shiteng Zhao, Ruopeng Zhang, Yan Chong, Xiaoqing Li, Anas Abu-Odeh, Eric Rothchild, Daryl C. Chrzan, Mark Asta, J. W. Morris, Andrew M. Minor
Summary: The study revealed that electropulsing enhances cross-slip and twinning during the mechanical deformation of Ti-Al (7% Al) alloy, preventing dislocations from localizing into planar slip bands and delaying the early failure of the alloy during tension.
Article
Multidisciplinary Sciences
Yan Chong, Max Poschmann, Ruopeng Zhang, Shiteng Zhao, Mohammad S. Hooshmand, Eric Rothchild, David L. Olmsted, J. W. Morris, Daryl C. Chrzan, Mark Asta, Andrew M. Minor
Article
Materials Science, Multidisciplinary
Iyad Alabd Alhafez, Carlos J. Ruestes, Shiteng Zhao, Andrew M. Minor, Herbert M. Urbassek
Summary: This study investigates nanoindentation behavior of a CoCrNi medium-entropy alloy using diffraction-contrast scanning transmission electron microscopy and molecular dynamics simulation. The results show that at low temperature, the alloy exhibits increased hardness, higher dislocation density at the pit boundary, and more fragmented twinning boundaries indicating reduced twin growth.
Article
Multidisciplinary Sciences
D. Giuntini, S. Zhao, T. Krekeler, M. Li, M. Blankenburg, B. Bor, G. Schaan, B. Domenech, M. Mueller, I Scheider, M. Ritter, G. A. Schneider
Summary: Supercrystalline nanocomposites consist of organically functionalized inorganic nanoparticles arranged into periodic structures with superlattice imperfections. When subjected to indentation, these materials exhibit deformation patterns similar to those seen in single crystals, accommodating plastic deformation through pile-ups, dislocations, and slip bands. The behavior of supercrystalline nanocomposites can be well described by classic shear theories of crystalline materials, displaying elastoplastic behavior along with compaction.
Article
Multidisciplinary Sciences
Shiteng Zhao, Ruopeng Zhang, Qin Yu, Jon Ell, Robert O. Ritchie, Andrew M. Minor
Summary: Nanostructured metals are usually strong due to high internal boundary density, limiting dislocation mean free path, but also more brittle. Nanotwinned materials can overcome this trade-off. A new nanostructuring method enhances the strength and ductility of titanium.
Article
Materials Science, Multidisciplinary
S. Zhao, B. Li, B. A. Remington, C. E. Wehrenberg, H. S. Park, E. N. Hahn, M. A. Meyers
Summary: Shock compression subjects materials to high pressure and shear stresses, leading to temperature increase and mechanisms of plastic deformation, eventually causing amorphization. Covalently bonded materials face greater difficulty in responding to this extreme environment of shock compression.
Review
Materials Science, Multidisciplinary
B. Y. Li, A. C. Li, S. Zhao, M. A. Meyers
Summary: Amorphization of crystalline structures is a common phenomenon in metals, ceramics, and intermetallic compounds, and can be achieved through mechanical deformation. This review focuses on the methods and experimental observations of amorphization induced by mechanical deformation, as well as the mechanisms of plastic deformation and computational simulations.
MATERIALS SCIENCE & ENGINEERING R-REPORTS
(2022)
Editorial Material
Multidisciplinary Sciences
Shiteng Zhao, Ruopeng Zhang, Qin Yu, Jon Ell, Robert O. Ritchie, Andrew M. Minor
Summary: This paragraph addresses the points raised by Guo et al., stating that their analysis is not supported and contains inconsistencies.
Article
Materials Science, Multidisciplinary
Cheng Zhang, Qin Yu, Yuanbo T. Tang, Mingjie Xu, Haoren Wang, Chaoyi Zhu, Jon Ell, Shiteng Zhao, Benjamin E. MacDonald, Penghui Cao, Julie M. Schoenung, Kenneth S. Vecchio, Roger C. Reed, Robert O. Ritchie, Enrique J. Lavernia
Summary: This research reports on a non-equiatomic, heterostructured high-entropy alloy FeNiCoAlTaB that exhibits remarkable combinations of mechanical properties across a wide temperature range. The alloy achieves its behavior by activating multiple individual mechanisms at different temperatures, providing a methodology for designing and fabricating multifunctional high-entropy alloys.
Article
Multidisciplinary Sciences
Shiteng Zhao, Sheng Yin, Xiao Liang, Fuhua Cao, Qin Yu, Ruopeng Zhang, Lanhong Dai, Carlos J. Ruestes, Robert O. Ritchie, Andrew M. Minor
Summary: The deformation and failure mechanisms of equiatomic CrCoNi medium-entropy alloy were investigated through powerful laser-driven shock experiments. Profuse planar defects, including stacking faults, nanotwins, and hexagonal nanolamella, were generated during shock compression, forming a three-dimensional network. The alloy exhibited strong tensile deformation and numerous voids were observed in the vicinity of the fracture plane during shock release. High defect populations, nanorecrystallization, and amorphization were found adjacent to these areas of localized deformation. Molecular dynamics simulations confirmed the experimental results and suggested that deformation-induced defects govern the growth of voids and delay their coalescence. These findings indicate that CrCoNi-based alloys are impact resistant, damage tolerant, and potentially suitable for applications under extreme conditions.
Editorial Material
Chemistry, Physical
Shiteng Zhao, Xiaolei Wu
Article
Materials Science, Multidisciplinary
Qianyong Zhu, Ran Li, Zezhou Li, Tao Zhang, Shiteng Zhao
Summary: A novel Ti-Zr-Hf-Nb-Ta-Cu-Be high-entropy MGMCs with improved high-temperature mechanical properties was developed through the multi-principle element alloying strategy of refractory elements. This provides an effective route to design high-performance high-entropy MGMCs for potential application in a wide temperature range.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Multidisciplinary Sciences
Shiteng Zhao, Zezhou Li, Chaoyi Zhu, Wen Yang, Zhouran Zhang, David E. J. Armstrong, Patrick S. Grant, Robert O. Ritchie, Marc A. Meyers
Summary: High-entropy alloys (HEAs) show remarkable material properties under harsh conditions, with structures containing stacking faults, twins, transformation between crystal structures, and amorphization being generated through plastic deformation processes.
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.
