Article
Nanoscience & Nanotechnology
Jungsub Lee, Hyunjong Ha, Jae Bok Seol, Jung Gi Kim, Eun Hyeok Seo, Seung Ki Moon, Im Doo Jung, Hyokyung Sung
Summary: In order to compensate for the porosity of high-speed printed Ti-6Al-4V specimens, a hot isostatic pressing (HIP) process was applied, which led to a deterioration phenomenon critically affected by the surface roughness of the as-built state. Efficient control can be achieved through setting the build angle.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Minhan Fang, Ying Li, Yuanfei Han, Jianwen Le, Guangfa Huang, Xianghai Chai, Liming Lei, Weijie Lu
Summary: In this study, in-situ SEM tensile investigations were conducted to study the fracture mechanism and anisotropic behavior of selective laser melted and then heat-treated Ti6Al4V. The results showed that surface steps were formed during the plastic stage, and microcracks were mainly initiated by the separation or fracture of adjacent lamellae. Surface defects induced strain concentration and premature failure, while defects inside the specimens had little effect on ductility.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
K. M. Bertsch, T. Voisin, J. B. Forien, E. Tiferet, Y. Ganor, M. Chonin, Y. M. Wang, M. J. Matthews
Summary: Effective optimization of Ti-6Al-4 V production using AM requires understanding the importance of different microstructural features to deformation and failure mechanisms. This study compared the tensile response and deformation mechanisms of EBM and SLM AM Ti-6Al-4 V materials and evaluated the influence of phase distribution, defect density, and porosity on material strength and ductility. The results suggest that phase distribution and defect density are crucial for determining material strength and maximum strain to failure, while porosity limits part ductility.
MATERIALS & DESIGN
(2022)
Article
Chemistry, Physical
Jiming Lv, Kaiyu Luo, Haifei Lu, Zhao Wang, Jiajun Liu, Jinzhong Lu
Summary: This research investigated the influences of laser shock peening (LSP) on the residual stress state, microstructures, and mechanical properties of Ti-6Al-4V alloy fabricated by selective laser melting (SLM). The results showed that LSP treatment adjusted the residual stress from tensile to compressive state and promoted the formation of high-density dislocations and parallel nano mechanical twins (nano-MTs) in the coarse lamellar alpha' structures, resulting in grain refinement. The ultimate tensile strength and elongation of the SLMed Ti-6Al-4V alloy increased by approximately 14.3% and 18.3% after LSP treatment, respectively. The study revealed that the combination of high levels of compressive residual stress and grain refinement achieved by LSP contributed to the enhancement of both strength and ductility in the alloy.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Jie Liu, Kai Zhang, Jianwen Liu, Yongfeng Xu, Ruifeng Zhang, Zhuoran Zeng, Yuman Zhu, Aijun Huang
Summary: The investigation focused on how microstructure characteristics determined the grain deformation behavior of Ti-6Al-4V in laser powder bed fusion. The orientation, thickness, and elongation direction of alpha laths were found to significantly impact the strain accumulation during uniaxial tensile process. The findings provide insights into deformation behavior related to lamellar structure in LPBF Ti64 and facilitate mechanical property manipulation.
MATERIALS CHARACTERIZATION
(2022)
Article
Materials Science, Multidisciplinary
A. E. Davis, J. Donoghue, J. R. Kennedy, N. Byres, P. B. Prangnell
Summary: In-situ cooling experiments were conducted on Ti64 samples for the first time, revealing the development of alpha colonies. Primary alpha laths play a crucial role in influencing subsequent colony growth and transformation process by nucleating secondary alpha laths through sympathetic autocatalysis.
Article
Materials Science, Multidisciplinary
Seunghee A. Oh, Rachel E. Lim, Joseph W. Aroh, Andrew C. Chuang, Benjamin J. Gould, Behnam Amin-Ahmadi, Joel Bernier, Tao Sun, P. Chris Pistorius, Robert M. Suter, Anthony D. Rollett
Summary: The microstructures of Ti-6Al-4V following laser processing depend primarily on the phase transformation of beta to alpha, with cooling rates inferred to be a key factor in determining the transformation threshold. High-speed synchrotron X-ray diffraction has revealed a new threshold between martensitic and diffusional phase transformation in Ti-6Al-4V occurring at higher cooling rates than previously reported.
MATERIALS RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Tom McKenna, Charles Tomonto, Greg Duggan, Eoin Lalor, Seamus O'Shaughnessy, Daniel Trimble
Summary: As-built, SLM-printed Ti-6Al-4V parts have brittle microstructures due to the formation of metastable a'-phase martensite. Post-processing heat treatments are needed to alleviate residual stress and decompose the martensite. This research evaluates the effect of unconventional 'cyclical' heat treatment parameters on grain morphology, phase composition, and mechanical performance, and compares it to a typical lamellar microstructure.
MATERIALS & DESIGN
(2023)
Article
Chemistry, Physical
Fei Lv, Huixin Liang, Deqiao Xie, Yuyi Mao, Changjiang Wang, Lida Shen, Zongjun Tian
Summary: The study proposes a mesoscale model to reveal the pore elimination mechanism in Ti-6Al-4V alloy during laser re-melting process. It is found that an appropriate re-melting scanning speed can effectively improve the material density and surface quality.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
Hailiang Li, Dechang Jia, Zhihua Yang, Xingqi Liao, Haize Jin, Delong Cai, Yu Zhou
Summary: Post heat treatment significantly influences the microstructure evolution and mechanical properties of SLM-fabricated Ti-6Al-4V alloy and titanium matrix composite. The TiB precipitates in the TMC samples grew into larger whiskers with improved mechanical performance after heat treatment. A finer dual-phase matrix microstructure was achieved for TMC samples with higher yield strength after heat treatment.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Manufacturing
Yang Liu, Huaizhong Xu, Binyi Peng, Xiaofeng Wang, Shuxin Li, Qun Wang, Zhiguo Li, Yonggang Wang
Summary: The paper systematically studied the influence of heating treatment on the microstructure and dynamic tensile properties of Ti-6Al-4 V alloy processed by selective laser melting. It was found that the strength gradually decreased as the heating temperature increased, while the strain to fracture initially increased and then tended to drop after exceeding 13 transus. Good balance of strength and ductility can be achieved with alpha + 13 treatment.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Engineering, Mechanical
A. K. Syed, D. Parfitt, D. Wimpenny, E. Muzangaza, B. Chen
Summary: The cyclic deformation and damage mechanisms in electron-beam-melted Ti-6Al-4V have been investigated. The as-built samples exhibit a graded microstructure, with larger alpha-laths and higher plastic strain in the top samples. After hot isostatic pressing (HIPing), the alpha-lath width increases and grain misorientation decreases, resulting in reduced microstructural and property gradients. In both conditions, the observed cyclic softening is caused by a reduction in friction stress and an increase in grain misorientation, indicating the fragmentation of the lath structure into smaller grains. As-built samples typically show lower fatigue life due to crack initiation from gas pores and lack-of-fusion defects.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Chemistry, Physical
Lujing Hao, Jiankun Liu, Yulong Li
Summary: Selective laser melting (SLM) is suitable for manufacturing complex parts, but faces challenges when making large parts. Small SLMed TC4 parts can be joined together through brazing or welding. Evaluation of the wettability of AgCuTi on SLMed TC4 surface is essential before joining, and wetting and spreading tests must be conducted.
Article
Materials Science, Multidisciplinary
Deepak Sharma, Somashekhar S. Hiremath, Nagesha Bommanahalli Kenchappa
Summary: In this study, the porous structure of Euplectella aspergillum has been used as a model to mimic mechanical metamaterial. The metamaterials were fabricated using a selective laser melting process and tested under compressive loading conditions. The effect of heat treatment on the mechanical behavior and microstructure was also investigated. The results showed that heat treatment increased the ductility of the metamaterial due to the formation of beta-Ti phase and a decrease in residual stresses. Finite element simulation demonstrated that diagonal struts in the E. aspergillum-based metamaterial prevented global buckling and improved the strength by uniformly distributing the load.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Lei Huang, Shunli Zheng, Yue Qin, Jianyang Han, Yanxin Qiao, Jian Chen
Summary: The corrosion behavior of a Ti-6Al-4V alloy prepared using selective laser melting (SLM) in a 0.1 mol/L NaOH solution was studied and compared with a commercially forged Ti-6Al-4V alloy. The commercially forged alloy showed higher corrosion resistance, which can be attributed to the presence of more active spots on the alloy surface and more defects in the passive films.
Article
Materials Science, Multidisciplinary
Shaolou Wei, Gaoming Zhu, Cemal Cem Tasan
Summary: Microstructural plastic strain distribution evolution is highly heterogeneous even in single-phase alloys. The transfer of slip/twinning across grain/phase boundaries plays a crucial role in governing this heterogeneity. Understanding of the fundamentals of transfer across grain boundaries has received significant attention, while knowledge about phase boundaries remains relatively limited.
Article
Materials Science, Multidisciplinary
Bijin Zhou, Leyun Wang, Jinhui Wang, Alireza Maldar, Gaoming Zhu, Hailong Jia, Peipeng Jin, Xiaoqin Zeng, Yanjun Li
Summary: The dislocation behavior of Mg-5Y alloy during tensile deformation was quantitatively studied using in-situ tensile test, VPSC modeling, and TEM. Results showed that <a> dislocations were the primary contributors to deformation, with a small fraction of <c+a> dislocations activated near grain boundaries. The alloy exhibited a lower CRSS ratio and high ductility, attributed to the mobility of <c+a> dislocations.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Bijin Zhou, Yanjun Li, Leyun Wang, Hailong Jia, Xiaoqin Zeng
Summary: In this study, the basal-slip-induced non-basal < a > slip behavior in a Mg-Y alloy was investigated using in-situ SEM/EBSD. It was found that the disorientation angles of grain boundaries and the plane orientation of local grain boundaries play significant roles in slip transfer behavior.
Article
Engineering, Mechanical
Sheng Zhang, Leyun Wang, Gaoming Zhu, Martin Diehl, Alireza Maldar, Xiaoqing Shang, Xiaoqin Zeng
Summary: In this study, machine learning was used to predict grain boundaries susceptible to damage, and the characteristics and importance of these boundaries were analyzed through simulations and classification models, providing new knowledge for understanding the behavior of metallic materials.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Jianzhong Zhang, Erik B. Watkins, Donald W. Brown, Bjorn Clausen, Peter Kenesei, Jun-Sang Park
Summary: In-situ time-resolved synchrotron wide-angle and small-angle x-ray scattering (WAXS/SAXS) were used to study the homogenization of phase and composition in segregated U-6Nb. The results show that the integrated SAXS intensities correlate well with variations of lattice parameter, solute redistribution, and phase fraction, especially the volume fractions of orthorhombic alpha-uranium in the segregated alloy. The combined datasets reveal that the phase and compositional homogenization processes within the probed volume are rapid during heating above the monotectoid temperature, completed within approximately 15 s and 60 s, respectively.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Ruixue Liu, Jie Wang, Leyun Wang, Xiaoqin Zeng, Zhaohui Jin
Summary: This study investigates the interactions between {10-12} twin boundaries and solute clusters in Mg-Zn-Ca alloys. It is found that the hindering effects of Zn/Ca-containing clusters on twin boundaries require a shear stress increment of 100 MPa, with a Ca content > 50 at%. The cluster hardening effects on twinning are positively correlated to the Ca content and the size of the clusters in Mg-Zn-Ca alloys.
Article
Engineering, Manufacturing
Leyun Wang, Zhe Song, Xuan Zhang, Jun-Sang Park, Jonathan Almer, Gaoming Zhu, Yiwen Chen, Quan Li, Xiaoqin Zeng, Yanjun Li
Summary: Laser powder bed fusion (LPBF) is an advanced technology for creating metallic components with complex geometry. By tailoring the alloy composition, the ductility and mechanical isotropy of LPBF Ti64 components can be significantly improved.
ADDITIVE MANUFACTURING
(2022)
Article
Materials Science, Multidisciplinary
Shunzi Luo, Leyun Wang, Jingya Wang, Gaoming Zhu, Xiaoqin Zeng
Summary: Laves phases with the AB2 stoichiometry are commonly found in Mg alloys. It is generally believed that Laves phases are detrimental for Mg's ductility. However, recent studies have shown that in Mg-Al-Ca alloys, the Al2Ca phase can deform plastically, resulting in high ductility and strong work hardening.
Article
Materials Science, Multidisciplinary
J. -S. Park, A. C. Chuang, J. Okasinski, H. Chen, P. Shade, T. J. Turner, S. Stock, J. Almer
Summary: This paper describes a new residual strain mapping program at the Advanced Photon Source, Argonne National Laboratory. Based on energy dispersive x-ray diffraction, the program is capable of accurately measuring the residual strain field of engineering alloys with high spatial and strain resolution, while providing a complementary view of the structure for a better understanding of the measured strain field.
EXPERIMENTAL MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Dingchang Zhang, Christoph Kenel, David C. Dunand
Summary: Microlattices with orthogonal 0-90 degrees architecture are 3D-extrusion printed and synthesized into equiatomic CoCrCuFeNi microlattices through H 2 -reduction and interdiffusion processes. Liquid-sintered microlattices show higher compressive strength and ductility, suitable for complex load-bearing applications.
Article
Materials Science, Multidisciplinary
Yinbin Miao, Kun Mo, Jun-Sang Park, Jonathan Almer, Caleb Massey, Cody Havrilak, Andrew T. Nelson, Heather Connaway, Abdellatif M. Yacout
Summary: The microstructure evolution of ultrasonic additive manufactured (UAM) zirconium during room temperature uniaxial tensile straining was evaluated using the Advanced Photon Source (APS) facility. In situ synchrotron tensile tests and wide-angle X-ray scattering (WAXS) scanning were conducted to uncover the changes in microstructure. Quantification of elastic and plastic deformation mechanisms within the strained specimens was achieved using various WAXS data analysis methods. Stress concentrations identified during plastic deformation were found to be correlated with fabrication defects, providing guidance for improving the UAM zirconium fabrication process.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Behnam Ahmadikia, Leyun Wang, M. Arul Kumar, Irene J. Beyerlein
Summary: By using mechanical testing, scanning electron microscopy, and a unified crystal plasticity framework, this study examines the intense and localized slip bands on prismatic planes and {1012} 1011 tensile twins in commercially pure titanium, as well as their transmission across grain boundaries. The results demonstrate that the orientation and curvature of the grain boundaries significantly affect the local stress fields and consequently the transmission of slip/twin. The neighboring grain properties, including active slip systems, slip bands, and twins, also play a crucial role in the deformation mechanisms.
Article
Nanoscience & Nanotechnology
Sheng Zhang, Gaoming Zhu, Yunhao Fan, Xiaoqin Zeng, Leyun Wang
Summary: Understanding the initiation of grain boundary (GB) damage is important for designing Mg alloys with improved ductility. In-situ tensile tests were conducted on two Mg alloy samples of different textures and GB damages were observed at 5.8% and 7.5% of the GBs before fracture. Statistical correlations between GB damage and certain GB features were identified. A machine learning model was built to predict GB damage initiation based on feature values, achieving AUC scores of 73.7% and 84.1% for the two samples. The most influential features include crystallographic c-axis misalignment, average grain size, and GB inclination with respect to the loading axis. The reasons for unpredictable GB damages are also discussed.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Zhe Song, Xiaoqin Zeng, Leyun Wang
Summary: This study investigates the influence of aluminum content on the microstructure and mechanical properties of LPBF Ti-xAl-4 V alloys. The results show that the strength of Ti-4Al-4V and Ti-8Al-4V alloys increases with increasing aluminum content, accompanied by higher work hardening and uniform elongation values compared to Ti64. This outcome is attributed to the activation of multiple slip modes in Ti44 and a more heterogeneous microstructure in Ti84.
MATERIALS RESEARCH LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Yunhao Fan, Gaoming Zhu, Jun-Sang Park, Xuan Zhang, Zhe Song, Huamiao Wang, Xiaoqin Zeng, Leyun Wang
Summary: Synergy between Ca and other alloying elements can modify the microstructure and mechanical properties of Mg alloys. However, the addition of Ca did not significantly improve the tensile properties of the alloys studied. This can be attributed to the softening effect of Ca on Mg's slip systems and the offsetting of increased yield strength by reduced Al solute strengthening. Additionally, the presence of a high amount of Al compromised the texture weakening and ductility enhancement reported in Mg-Zn-Ca ternary alloys.
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.
