Article
Materials Science, Multidisciplinary
Dong-Ming Jin, Zhen-Hua Wang, Jin-Feng Li, Ben Niu, Qing Wang
Summary: This study investigated the formation and strengthening mechanism of coherent BCC/B2 microstructure in Al-Ti-Zr-Nb-Ta-Cr/Mo refractory high-entropy alloy system. It found that the alloy with Cr0.5Mo0.5 exhibited the best mechanical performance after aging at 873 K.
Article
Chemistry, Physical
E. Panina, N. Yurchenko, S. Zherebtsov, N. Stepanov
Summary: The response of Ti40Nb30Hf15Al15 and Ti40Nb30Zr20Al10 refractory high entropy alloys to annealing was investigated in this study. Different grain sizes and phase compositions were observed after cold rolling and annealing at different temperatures, leading to varying degrees of hardness changes in the alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Takuma Teramae, Takayuki Tanaka, Mizuki Fukuo, Kazuki Shitara, Junko Umeda, Shufeng Li, Abdulaziz Alhazaa, Katsuyoshi Kondoh
Summary: Commercial pure Ti alloys are often used in biomedical applications, but they need to be strengthened by adding alloying elements. Ti-Fe alloys modified with Zr were investigated in this study to produce high-strength, ductile, and biocompatible alloys. The addition of Zr solid solution increased lattice constants and refined grain size, leading to improved mechanical properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
T. E. Whitfield, N. L. Church, H. J. Stone, N. G. Jones
Summary: Refractory metal high entropy superalloys (RSA) are being developed for high temperature structural applications. However, recently the microstructures of several RSA have been shown to be unstable, precipitating potentially deleterious intermetallic phases during prolonged exposure at elevated temperatures.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Sang-Hwa Lee, Jae-Gil Jung, Sung-Il Baik, Sung Hyuk Park, Min-Seok Kim, Young-Kook Lee, Kwangjun Euh
Summary: The addition of Ti refines the grain size, reduces phase agglomeration, and improves the strength and ductility of the alloy, with the extrusion forming a bimodal structure of fine DRXed grains and coarse unDRXed grains.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Alexandra Baranova, Sergey Dubinskiy, Natalia Tabachkova, Sergey Prokoshkin, Vladimir Brailovski
Summary: The dependence of isothermal omega(iso)-phase formation on heating, holding, and cooling conditions during the ageing of Ti-Nb-Zr shape memory alloys is insufficiently understood. This study investigates the crystal structure and morphology of the omega(is)(o)-phase in a thermomechanically treated Ti-22Nb-6Zr (at%) alloy during ageing under different temperature conditions using X-ray diffraction and transmission electron microscopy. The results show that the beta -> omega(iso) transformation exhibits C-shaped kinetics with a maximum at 300 degrees C, and the formation and growth of the omega-phase are mainly controlled by shear-related mechanisms and to a lesser extent, diffusion-related mechanisms.
Article
Materials Science, Multidisciplinary
Mingkang Wang, Junhao Yuan, Fengyun Yu, Qing Wang, Yufeng Liu, Zhongwei Zhang, Chuang Dong, Peter K. Liaw
Summary: This study investigated the formation and mechanical behavior of BCC Zr(Hf)-Nb-Ti medium entropy alloys, demonstrating the enhancement of BCC-beta structural stability with increasing Nb content and the improvement in mechanical properties with appropriate Ti and Hf/Ti additions. The designed alloys exhibited excellent mechanical properties, showing higher yield strength, larger elongation to fraction, and lower Young's modulus.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2021)
Article
Chemistry, Physical
Ka-Kin Wong, Hsueh-Chuan Hsu, Shih-Ching Wu, Wen-Fu Ho
Summary: Three nonequiatomic Ti-rich Ti-Zr-Nb-Mo medium-entropy alloys were developed for biomedical applications, exhibiting high yield strength, low elastic moduli, and excellent resilience. The distortion effect caused by alloying atomic radius difference contributed to the superior yield strengths of the alloys. Increasing Ti content can prevent segregation issues and reduce the elastic modulus.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Huang Liu, Jingxi Zhang, Chengshang Zhou, Pei Sun, Yong Liu, Zhigang Zak Fang
Summary: This paper investigates the effect of Nb alloying on the microstructure and hydrogen storage properties of Ti-Fe-Zr-Mn-Nbx alloys. The addition of 2% Nb enables a good combination of the hydrogen capacity and activation property, while Zr-rich phases play a critical role in the activation behavior. However, high Nb addition (> 4%) leads to the reduction of Zr-rich phases and deteriorates the activation kinetics. Nb addition also promotes the formation of the TiFe main phase and increases capacities at ambient temperature. The correlations between microstructure and hydrogen storage performance provide insights into tailoring hydrogen storage properties by alloying TiFe with multi-elements.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Robert Josef Enzinger, Martin Luckabauer, Norihiko L. Okamoto, Tetsu Ichitsubo, Wolfgang Sprengel, Roland Wurschum
Summary: A detailed understanding of the kinetics of phase formation in fi-stabilised titanium is crucial for their applicability, but specialized measurement techniques are needed due to the complex nature and long timescales of the transformations. High-stability isothermal laser dilatometry was used to study the volume changes of Ti-21 at. pct V samples during phase formation. Different behaviors were observed between samples with different solute oxygen content, and the temperature ranges for diffusionless and diffusion-assisted isothermal w-formation as well as w-to-a transformation were determined. The results confirm recent findings on the distinction between diffusionless and diffusion-assisted isothermal w formation modes. Modelling of w-phase formation using Austin-Rickett kinetics revealed temperature-dependent formation rates, which were used to develop isothermal TTT-diagrams reflecting the strong influence of oxygen content.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Tamsin E. Whitfield, George J. Wise, Ed J. Pickering, Howard J. Stone, Nicholas G. Jones
Summary: Refractory metal high entropy superalloys are considered as potential new high temperature structural materials with nanoscale cuboidal microstructures. This study investigated the microstructures produced by the Nb-Zr miscibility gap within the simpler Ti-Nb-Zr constituent system, suggesting that Nb-Zr interactions may not play a significant role in the formation of nanoscale cuboidal RSA microstructures during cooling.
Article
Materials Science, Multidisciplinary
Alexander V. Barashev, Qiang Zhao, Qingyu Wang, Qiang Yan, Fei Gao
Summary: This study investigates the formation of delta hydrides in zirconium cladding under radiation and thermal aging conditions through rate theory modeling. The preferential nucleation of platelet-shaped hydrides on grain boundaries was observed, and the importance of this modification in the precipitation model was analyzed. Comparisons of different approaches were made to understand the factors affecting hydride formation in the clad.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Min-Kyu Lee, Hyun Lee, Hyoun-Ee Kim, Eun-Jung Lee, Tae-Sik Jang, Hyun-Do Jung
Summary: The nano-topographical features of titanium-niobium-zirconium (TNZ) alloy surfaces were successfully controlled using the target-ion induced plasma sputtering (TIPS) technique. Various nanopatterns were fabricated on the surface of the TNZ alloys, with experimental groups showing superior biological functions when nanopattern widths were >= 130 nm.
Article
Nanoscience & Nanotechnology
Y. Alshammari, Y. Alkindi, B. Manogar, F. Yang, L. Bolzoni
Summary: This study investigates the effects of lean additions of zirconium on the microstructure and properties of powder metallurgy Ti-Zr alloys. It is found that incremental addition of zirconium enhances the densification and hardness, but decreases the ductility.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Physics, Applied
Yufei Wang, Yaojun Miao, Peng Peng, Haiyan Gao, Jun Wang, Baode Sun
Summary: The orientation at the interfaces significantly affects the morphology of aging precipitates in Al-Zr-Y composites. First-principles calculations reveal that the most stable orientation at the Al/Al-3(Zr,Y) interface is FCC-Al(001)/FCC-Al3Y(001). Zr and Y doping can lower the interface energies, with Y doping dominating the interface with the increase of substituted elements content.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Fangzhou Song, Takayuki Yamamoto, Takeshi Yabutsuka, Takeshi Yao, Shigeomi Takai
Summary: Lithium ion-conductive composites were prepared by dispersing LLTO particles in a LAGP matrix, leading to increased electrical conductivity. Lithium ions were found to be the predominant charge carrier in this composite electrolyte.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Electrochemistry
Fangzhou Song, Harunobu Onishi, Wen-Jauh Chen, Takeshi Yabutsuka, Takeshi Yao, Shigeomi Takai
Summary: In this study, TEM experiments were conducted on LaPO4-dispersed LATP composite to investigate the microstructure and compositions of the dispersed LaPO4 particles and surrounding LATP matrix. The results revealed an intimate contact between LaPO4 particle and the LATP matrix, suggesting the formation of a space charge layer at the interface to enhance conductivity.
Article
Chemistry, Physical
Fangzhou Song, Masayoshi Uematsu, Takeshi Yabutsuka, Takeshi Yao, Shigeomi Takai
Summary: LATP-based composite electrolytes were prepared by sintering mixtures of LATP precursor and La2O3 nano-powder, which showed that La2O3 could react with LATP to form dispersed LaPO4 particles. The room temperature conductivity initially increased with La2O3 addition but decreased above 6 wt.%, and the activation energy of conductivity remained relatively unchanged. Comparing with LATP-LLTO system, the LATP-La2O3 system achieved fine dispersion of LaPO4 particles despite a slight reduction in conductivity due to unidentified impurities.
Article
Electrochemistry
Shigeomi Takai, Ryo Takemoto, Takeshi Yabutsuka, Takeshi Yao
Summary: To investigate the influence of defect structure on oxide ion conduction properties in CaWO4-based system, cesium and lanthanum ions were doped into CaWO4. The results showed that the structure and phase transition of the solid solution varied in different composition regions, which affected the conductivity. The study revealed that high-temperature oxide ion conduction was attributed to both oxide ion vacancies and interstitials.
Article
Chemistry, Physical
Fangzhou Song, Heng Chen, Hirotoshi Hayashida, Tetsuya Kai, Takenao Shinohara, Takeshi Yabutsuka, Takeshi Yao, Shigeomi Takai
Summary: Lithium tracer diffusion coefficients were measured in LATP and LATP-LaPO4 composite solid electrolytes, indicating that bulk diffusion becomes the dominant mechanism at 300℃ to 500℃.
SOLID STATE IONICS
(2022)
Article
Multidisciplinary Sciences
Yusuke Takaoka, Shunsuke Fujibayashi, Takeshi Yabutsuka, Yuya Yamane, Chihiro Ishizaki, Koji Goto, Bungo Otsuki, Toshiyuki Kawai, Takayoshi Shimizu, Yaichiro Okuzu, Kazutaka Masamoto, Yu Shimizu, Makoto Hayashi, Norimasa Ikeda, Shuichi Matsuda
Summary: Sulfonation and applications of amorphous calcium phosphate can enhance the bioactivity of polyetheretherketone (PEEK). The precipitation of amorphous calcium phosphate after sulfonation (AN-treatment) can further improve the bone-bonding strength of PEEK. The study found that CPEEK subjected to AN-treatment had better bone-bonding strength at the interface with the base material compared to untreated CPEEK. AN-treatment promoted the formation of new bone, resulting in enhanced bonding between CPEEK and bone tissue.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Multidisciplinary
Hayato Nakaishi, Takeshi Yabutsuka, Takeshi Yao, Shinji Kitao, Makoto Seto, Wen-Jauh Chen, Yuta Shimonishi, Shuhei Yoshida, Shigeomi Takai
Summary: We characterized a mechanically alloyed (Fe2O3)1-x(Al2O3)x solid solution with corundum-type structure using TEM, EXAFS, and Mössbauer spectroscopy. The results showed the homogeneity of cation distribution and the variation of magnetic property with composition. HR-TEM revealed that the crystallite size of the solid solution is 10-20 nm and the lattice spacing is consistent with Vegard's law. EXAFS measurements indicated a monotonic decrease in Fe-Fe distance with aluminum substitution, while Fe-O was not significantly altered. Mössbauer spectroscopy showed a gradual change in spectra from sextet peaks at x = 0 to doublet with increasing Al2O3 concentration up to x = 0.67, suggesting homogeneous substitution of aluminum ions in the corundum-type structure.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Materials Science, Ceramics
Kenshiro Takaishi, Shigeomi Takai, Takeshi Yabutsuka
Summary: Octacalcium phosphate (OCP) coating was formed on the surface of Mg-Al-Zn-Ca alloy (AZX612) through anodic oxidation and subsequent immersion in a supersaturated aqueous solution containing phosphate and calcium ion. The formed OCP layer consists of an inner layer of fine crystallites and an outer layer of large crystallites, and the inner layer remains on the alloy even after ultrasonication process. AZX612 treated with both anodic oxidation and subsequent OCP coating process exhibits higher corrosion resistance than those treated with only anodic oxidation.
JOURNAL OF THE CERAMIC SOCIETY OF JAPAN
(2022)
Article
Materials Science, Ceramics
Takeshi Yabutsuka, Masaya Yamamoto, Shigeomi Takai
Summary: This study aimed to establish enzyme immobilization technology using maghemite/hydroxyapatite composite particles and investigate the enzyme adsorption characteristics. The results showed that the enzyme's isoelectric point and the solution's pH influenced the immobilization. The interaction between HA on the composite particles and the adsorbed enzymes was strongest when pH-pI was 1-2.
JOURNAL OF THE CERAMIC SOCIETY OF JAPAN
(2022)
Article
Materials Science, Ceramics
Shigeomi Takai, Yoshinobu Tawa, Masashi Takemoto, Jian Kang, Takeshi Yabutsuka, Takeshi Yao
Summary: LiMn2O4 was prepared by high-energy ball-milling and one-pot sintering, with optimized milling time leading to enhanced cathode performance and reduced structural changes during charging, thus improving cycle performance.
JOURNAL OF THE CERAMIC SOCIETY OF JAPAN
(2021)
Article
Electrochemistry
Jian Kang, Shigeomi Takai, Takeshi Yabutsuka, Takeshi Yao
Summary: The structural variation of NCM-811 during lithium extraction to the high-voltage region shows the generation and transformation between H3 and H2 phases. The Ni interlayer distance decreases with relaxation time, possibly due to an increase in the valence of Ni.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
