Article
Chemistry, Physical
Peng Peng, Li Lu, Zijie Liu, Yuanli Xu, Xudong Zhang, Zhikun Ma, Hong Zhang, Min Guo, Lin Liu
Summary: The microstructure evolution in directionally solidified Ni-based superalloys with different Ta compositions was investigated. It was found that the addition of Ta promoted element segregation in the interdendritic region and increased the volume fraction of MC carbides and eutectics. Furthermore, the dendrite arm spacing and solidification range of these superalloys were found to increase with increasing Ta composition.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Xueqiao Li, Yinong Liu, Yunsong Zhao, Yanhui Chen, Ang Li, Jianfei Zhang, Yadi Zhai, Zhipeng Li, Dongfeng Ma, Xiaochen Li, Qing Zhang, Xiaomeng Yang, Haibo Long, Shengcheng Mao, Ze Zhang, Xiaodong Han
Summary: This study investigates the oxidation and fracture behaviors of a thin Ni-based single crystal superalloy component at 650 degrees C under stress using an in-situ thermal-stress environmental transmission electron microscope. It was found that in-situ oxidation changed the tensile fracture mode from plastic fracture on {111} planes to brittle fracture on {001} planes adjacent to the gamma/gamma interfaces. Microanalysis also revealed different oxidation behaviors of gamma ' cuboids, gamma phase, and gamma/gamma interface, highlighting the thickness debit effect.
MATERIALS RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Yun Zhang, Xiaojie Xu
Summary: This study focuses on the unique microstructure of Ni-based single crystal superalloys and the lattice misfit between gamma and gamma' phases. By developing a Gaussian process regression model, the researchers are able to predict lattice misfits based on chemical composition, temperature, and two morphological indicators. This model is highly stable, accurate, and promising for fast, robust, and low-cost lattice misfit estimations.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Nanoscience & Nanotechnology
L. Heep, D. Burger, C. Bonnekoh, P. Wollgramm, A. Dlouhy, G. Eggeler
Summary: The low temperature high stress tensile creep behavior of the superalloy single crystal ERBO-1 was investigated, with comparisons made between loading directions of [001] and deviations towards [111] and [011]. The study found that creep rates are influenced by the loading directions, and faster creep rates are observed when dislocations from two octahedral systems experience similar driving forces.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Multidisciplinary
Bingyao Liu, Qi Chen, Zhaolong Chen, Shenyuan Yang, Jingyuan Shan, Zhetong Liu, Yue Yin, Fang Ren, Shuo Zhang, Rong Wang, Mei Wu, Rui Hou, Tongbo Wei, Junxi Wang, Jingyu Sun, Jinmin Li, Zhongfan Liu, Zhiqiang Liu, Peng Gao
Summary: This study demonstrates the successful fabrication of low-strain single-crystalline nitride films on highly mismatched substrates via graphene-assisted remote heteroepitaxy. By weakening the interface potential and smoothing the atomic steps with graphene, the dislocation density caused by lattice mismatches is significantly reduced, leading to the fabrication of a yellow light-emitting diode.
Article
Materials Science, Multidisciplinary
Adelajda Polkowska, Sebastian Lech, Piotr Bala, Wojciech Polkowski
Summary: This study systematically examined the effect of heat-treatment temperature on the structural evolution and mechanical response of Haynes (R) HR-224 (R) alloy, revealing a significant increase in room temperature tensile strength and a reduction of ductility under 600-800 degrees C/2 h heat treatment conditions. Discontinuous precipitation (DP) of (gamma + gamma')/M23C6 was identified as the main structural process affecting the observed mechanical behavior of the material.
MATERIALS CHARACTERIZATION
(2021)
Article
Multidisciplinary Sciences
Xuexi Yan, Yixiao Jiang, Qianqian Jin, Tingting Yao, Weizhen Wang, Ang Tao, Chunyang Gao, Xiang Li, Chunlin Chen, Hengqiang Ye, Xiu-Liang Ma
Summary: By combining transmission electron microscopy, first-principles calculations, and cathodoluminescence spectroscopy, we demonstrate unexpected strong interfacial interactions at the incoherent AlN/Al2O3 (0001) interface with a large mismatch, which result in the formation of misfit dislocation networks and stacking faults rarely observed at other incoherent interfaces. The strong interfacial interactions significantly tailor the interfacial atomic structure and electronic properties, leading to a reduced band gap and strong interfacial ultraviolet light emission. These findings suggest the potential of incoherent interfaces in developing novel heterojunction materials and devices.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Jiali Gao, Yang Tong, Hua Zhang, Lilong Zhu, Qingmiao Hu, Jiahao Hu, Shangzhou Zhang
Summary: By integrating composition and high-temperature mechanical performance into machine learning, a workflow was proposed to optimize commercial K403 superalloys for increased service temperature of hot-end parts in aircraft engines and gas turbines. The machine learning model successfully selected 7 superalloys, one of which exhibited improved creep rupture life compared to the commercial K403 alloy.
MATERIALS CHARACTERIZATION
(2023)
Article
Engineering, Mechanical
Jia Gao, Hongwei Li, Xinxin Sun, Xin Zhang, Mei Zhan
Summary: This study developed an electro-thermal-mechanical crystal plasticity model to investigate the multiscale deformation mechanism of materials during electrically assisted formation. The model considered the effects of Joule heating and nonthermal effects, as well as the influence of current density threshold on dislocation density and slip resistance. The model provides a quantitative method to analyze the electrically assisted formation process.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Zhenghao Chen, Kyosuke Kishida, Haruyuki Inui, Martin Heilmaier, Uwe Glatzel, Gunther Eggeler
Summary: The effects of Ni and Ta additions on the mechanical properties of Co-based superalloys were investigated. The additions of Ni and Ta increased the yield strength at intermediate and high temperatures by increasing the stability of the L1(2) phase. The strength increase at intermediate temperatures can be attributed to the increased complex stacking fault energy and the increased anti-phase boundary energy on (111) planes. The strength increase at high temperatures is mainly due to the increased L1(2) solvus temperatures.
Article
Materials Science, Multidisciplinary
F. D. Leon-Cazares, R. Schlutter, F. Monni, M. C. Hardy, C. M. F. Rae
Summary: This study provides experimental evidence, using transmission electron microscopy, for the nucleation mechanism of superlattice intrinsic stacking faults (SISF) in polycrystalline alloys. The concept of a nascent fault is introduced, and the stress and dislocation types involved in the subsequent dislocation evolution are detailed.
Article
Materials Science, Ceramics
Lingfeng He, Tiankai Yao, Kaustubh Bawane, Miaomiao Jin, Chao Jiang, Xiang Liu, Wei-Ying Chen, J. Matthew Mann, David H. Hurley, Jian Gan, Marat Khafizov
Summary: The early stage of microstructural evolution of ThO2 under krypton irradiation was studied using in situ transmission electron microscopy (TEM). The growth rate and density of dislocation loops were investigated with changing irradiation temperature and ion dose. Different types of dislocation loops were determined using various TEM techniques, and diffusion coefficients of different defects were extracted using a rate theory model.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
Ryan B. Sills, Douglas L. Medlin
Summary: The characterization of the three-dimensional arrangement of dislocations is important for many analyses in materials science. This paper presents a semi-automated object-based approach that reduces data collection requirements by utilizing the prior knowledge that dislocations are line objects.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Nanoscience & Nanotechnology
Yanhui Chen, Wenhan Zhang, Yunsong Zhao, Yadi Zhai, Bin Zhang, Hui Lu, Guo Yang, Luyan Yang, Ang Li
Summary: Rhenium is crucial in enhancing the mechanical properties of gamma/gamma' structure single-crystal Ni-based superalloys, but its oxidation-induced evaporation can lead to a decrease in corrosion resistance. The in situ Re evaporation process in a high Re-containing Ni-based superalloy was observed, showing local aggregation in the gamma phase and subsequent formation of channels for accelerated oxidation. This real-time oxidation process of Re evaporation offers detailed nanoscale information on corrosive gas resistance properties.
SCRIPTA MATERIALIA
(2021)
Article
Nanoscience & Nanotechnology
Yawei Li, Li Wang, Yufeng He, Wei Zheng, Langhong Lou, Jian Zhang
Summary: The study found that as the temperature increases, the spacing of dislocation networks in the gamma/gamma' interface decreases, while the minimum creep rate increases non-linearly. This is due to the enhanced dislocation-climb in the interface and gamma'-cutting by a <010> superdislocations.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Yingchao Li, Bashir S. Shariat, Hong Yang, Satyajit Sarkar, Junsong Zhang, Yunzhi Wang, Denis Favier, Yinong Liu
Summary: NiTi shape memory alloys exhibit Luders-type deformation due to stress-induced martensitic transformation. Various explanations have been proposed, but they contradict experimental evidence. In this study, a new model based on the conservation of sample length changes, crosshead movement, and elastic contraction is proposed and verified through experiments and measurements. The new model can describe the upper-lower yielding phenomenon and the plateau stress in Luders-type deformation behavior.
Article
Materials Science, Multidisciplinary
Zibing An, Shengcheng Mao, Yinong Liu, Luyan Yang, Ashok Vayyala, Xiao Wei, Cheng Liu, Caijuan Shi, Huixin Jin, Cuixiu Liu, Jianxin Zhang, Ze Zhang, Xiaodong Han
Summary: In this study, a strategy of using a heterogeneous grain size structure and a reduced stacking fault energy was explored in a CoCrFeNiMn FCC high entropy alloy to overcome the strength-ductility trade-off. The alloy achieved high yield strength, tensile strength, and elongation to failure through cooperative strain hardening mechanisms. These micromechanisms of deformation helped refine the mean free paths for dislocations and improve the alloy's hardness.
Article
Chemistry, Physical
Won-Tae Lee, Jong-Taek Yeom, Jung Gi Kim, Jeong Seok Oh, Taekyung Lee, Yinong Liu, Shuanglei Li, Tae-Hyun Nam
Summary: This study investigates the microstructure evolution and nanoindentation behavior of a Ti-20Zr-9Nb-4Sn alloy aged at 600 degrees C, demonstrating the potential for precipitation strengthening effect of (Zr,Sn)-rich precipitates. The results show that the hardness of the aged specimens initially increases and then reaches a plateau as aging time prolongs. The (Zr,Sn)-rich precipitates exhibit higher hardness than the alpha precipitate and matrix, indicating their contribution to the overall hardness of the specimen.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Yingchao Li, Bashir S. Shariat, Hong Yang, Yinong Liu
Summary: NiTi shape memory alloys exhibit Luders-type deformation in tension. We propose a new explanation of the mechanism of this behaviour based on a mechanical criterion of sample length change conservation among three contributions, including machine displacement, Luders band elongation and elastic strain contraction, and established a mathematical model to describe the behaviour.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Yingchao Li, Junsong Zhang, Martin Saunders, Yang Ren, Hong Yang, Yinong Liu
Summary: By utilizing the principles of lattice strain matching and collective atomic load transfer, ultralarge elastic strains were induced in a brittle NiTi-Nb3Sn eutectic composite, where Nb3Sn lamellae achieved a remarkable elastic lattice strain of -2.4%. This study both tests the applicability of lattice strain matching in brittle materials and explores a novel fabrication approach for in-situ composites via eutectic solidification.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Chemistry, Physical
Bashir S. Shariat, Hong Yang, Yinong Liu
Summary: This study examines the formation and propagation process of Luders bands in parallel-graded NiTi samples during stress-induced martensitic transformation. Digital image correlation is used to measure the full-field strain. The samples with varying width profiles experience progressively increasing load and continuous variation of width during the transformation process. The size of the Luders band front transition zone remains constant, but the local strain rate varies. The transition zone of the forward transformation is wider and has a lower strain rate compared to the reverse transformation.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Yuru Zha, Daqiang Jiang, Yinong Liu, Genfa Kang, Hui Zhang, Xiaohua Jiang, Lishan Cui
Summary: By observing the Elinvar effect in non-magnetic Co-doped TiNi alloys, we added a small amount of Nb to Ti50Ni41Co9 alloy with low Co content to regulate the phase transformation behaviors and induce Elinvar effect. The effects of Nb content on the phase transformation behaviors and temperature dependences of elastic moduli were studied. Ti50Ni41Co9 alloy exhibited B2->R phase transformation during cooling, but it was suppressed by the increase of Nb content and converted to a continuous transformation over a broad temperature range.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Sam Bakhtiari, Arpit Agrawal, Hong Yang, Reza Mirzaeifar, Lishan Cui, Daqiang Jiang, Yinong Liu
Summary: The paper presents a unique phenomenon observed in a NiTi-Nb nanowire in-situ composite system, where the B2 NiTi matrix undergoes amorphization due to the diffusion of Nb through the B2 lattice. The diffusion of Nb in the NiTi matrix is driven by Oswald ripening, which occurs during the fragmentation and granulation of Nb nanowires at elevated temperatures. The amorphization of the NiTi matrix is attributed to the formation of anti-site defects caused by the substitutional diffusion of Nb.
Article
Materials Science, Multidisciplinary
Hengzhe Wang, Haibo Long, Yinong Liu, Yunsong Zhao, Xueqiao Li, Guo Yang, Xiaomeng Yang, Yanhui Chen, Shengcheng Mao, Ze Zhang, Xiaodong Han
Summary: This study investigates the effect of Ru on the solution heat treatment window of a Ni-based single crystal superalloy. The addition of Ru influences the solidification microstructure and widens the window. Ru decreases the partition ratios between the dendrite core and dendrite edge regions, promotes the enrichment of Re at the γ/γ' phase interfaces, inhibits the formation of (Ta, X)C carbide, and helps to widen the solution treatment temperature window of the alloy.
MATERIALS CHARACTERIZATION
(2023)
Article
Multidisciplinary Sciences
Yan Lu, Yongchao Chen, Yongpan Zeng, Yin Zhang, Deli Kong, Xueqiao Li, Ting Zhu, Xiaoyan Li, Shengcheng Mao, Ze Zhang, Lihua Wang, Xiaodong Han
Summary: Understanding the nanoscale fracture processes and mechanisms in BCC metals is important for preventing failure. In this study, in situ atomic-resolution observations reveal the crack growth process and the effects of temperature and strain rate on crack growth. The results provide insights into the dislocation-mediated mechanisms of the ductile to brittle transition in BCC refractory metals.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Yingchao Li, Sam Bakhtiari, Hong Yang, Martin Saunders, Daqiang Jiang, Yinong Liu
Summary: This study investigated the effects of various point defects on the monoclinic angle of the B19 '' martensite in NiTi. It was found that different defects have different effects on the monoclinic angle, which in turn affects the characteristic strains of the alloy. These findings may provide insights into the variations of recoverable transformation strains of NiTi shape memory alloys observed experimentally.
SHAPE MEMORY AND SUPERELASTICITY
(2023)
Article
Materials Science, Multidisciplinary
Bashir S. Shariat, Yinong Liu
Summary: This study investigated the variation of the Poisson's ratio of a NiTi alloy during pseudoelastic deformation. The results showed that the Poisson's ratio of the alloy changed at different stages.
SHAPE MEMORY AND SUPERELASTICITY
(2023)
Article
Nanoscience & Nanotechnology
Zibing An, Shengcheng Mao, Cheng Jiang, Ziyao Li, Shichang Wu, Yadi Zhai, Li Wang, Yinong Liu, Ze Zhang, Xiaodong Han
Summary: A high-entropy alloy (HEA) with low stacking fault energy and high strength was designed using the principle of heterostructure strengthening. The alloy exhibited a multi-scale heterogeneous microstructure containing hierarchical twins. It achieved ultrahigh yield strength, ultimate tensile strength, and large ductility at low temperature, surpassing most FCC HEAs reported so far and breaking the strength-ductility trade-off of conventional metal alloys. The extraordinary mechanical properties were attributed to a suitable strain hardening capability resulting from the synergistic effect of hetero-deformation-induced hardening, twinning-induced plasticity, and deformation-induced phase transformation.
SCRIPTA MATERIALIA
(2024)
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.