Papers by Author: Akihisa Inoue

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Authors: Bao Long Shen, Chun Tao Chang, Akihisa Inoue
673
Authors: Akira Takeuchi, Akihisa Inoue
Abstract: The relationships of optimal compositions of bulk metallic glasses (BMGs) have been analyzed with a set of thermodynamic quantities of mismatch entropy normalized with respect to Boltzmann's constant (Sσ!/kB) and mixing enthalpy (Hmix) and with assistance of classification result of BMGs. The analysis shows clear dependence of the location of Sσ!/kB and Hmix values for optimal compositions of ternary BMGs in Sσ!/kB-Hmix chart in each alloy system. The ternary BMGs are summarized into four types: (1) Cu-based, (2) La-, Zr- and Ca-based, (3) Pd-based and (4) Fe- and Mg-based BMGs according to their maximum value of Sσ!/kB ((Sσ!/kB)max) and the largest and negative value of Hmix ((Hmix)L.N.) or their half values which are obtained for each system. These types of BMGs are related with the local arrangements of BMGs, which are widely accepted as an icosahedral structure for Metal-Metal type, a transformed tetragonal dodecahedrons and triacontrahedrons structure for Pd-Metalloid type, and a network-like structure for Metal-Metalloid type.
1988
Authors: Takamasa Onoki, Xin Min Wang, Sheng Li Zhu, Yasuto Hoshikawa, Naota Sugiyama, Masaru Akao, Eiichi Yasuda, Masahiro Yoshimura, Akihisa Inoue
Abstract: Apatite forming and bonding ability of Ti based bulk metallic glass ((Ti0.40Zr0.10Cu0.36Pd0.14)99Ca1: BMG) were investigated as a new type of biomaterials. Powder mixture of CaHPO4・2H2O and Ca(OH)2 and the BMG disks were treated with autoclave for hydrothermal hot-pressing simultaneously (150°C, 40MPa). And then the BMG disks were soaked in simulated body fluid (SBF, Kokubo solution). Apatite were deposited and covered on the surface of the BMG. It was firstly demonstrated that surface of Ti based bulk metallic glass could be revealed apatite forming ability.
249
Authors: Jian Bing Qiang, Liang Yuan, Qing Wang, Ying Min Wang, Chuang Dong, Wei Zhang, Akihisa Inoue
Abstract: With the aid of the atomic-cluster-plus-glue-atom model (ACPGA model) proposed by Dong et al [1] for bulk metallic glasses (BMGs), the formation and characteristic of Ni-Ta binary BMGs were investigated in this work. Binary glass-forming compositions containing 56.3–62.5 at.%-Ni were obtained by a composition formula [M-Ni6Ta6]Ni3 based on the ACPGA model. It was found that Ni-Ta BMGs with a diameter of 2 mm was obtained over a composition range of 59 ~ 62 at.%-Ni by copper mold casting method, which are in good agreement with our model prediction. Newly-developed Ni–Ta BMGs are a kind of extreme materials, which exhibit superior thermal stability (Tg = 993K) and a ultrahigh fracture strength of about 3.5 GPa.
395
Authors: Guo Qiang Xie, Dmitri V. Louzguine-Luzgin, Mikio Fukuhara, Akihisa Inoue
Abstract: Large-size Ni-based bulk metallic glass (BMG) composite samples exhibiting simultaneously high strength, enhanced plasticity and improved conductivity were produced by spark plasma sintering of mixed glassy powder blended with high-conductive Cu particulates. This opens new possibilities for the applications of the BMG composites as functional and structural materials.
197
Authors: Akihisa Inoue, T. Nakamura, N. Nishiyama, Taro Sugita, Tsuyoshi Masumoto
147
Authors: Alain Reza Yavari, S. Pang, Dmitri V. Louzguine-Luzgin, Akihisa Inoue, N. Lupu, N. Nikolov, G. Heunen
105
Authors: Akihiko Hirata, Yoshihiko Hirotsu, Kenji Amiya, Nobuyuki Nishiyama, Akihisa Inoue
Abstract: Nanoscale structural change in (Fe0.5Co0.5)72B20Si4Nb4 bulk glassy alloy on annealing has been investigated using transmission electron microscopy. On annealing at temperatures above 773K, electron diffraction intensity analysis showed a clear structure change for a Cr23C6-type local atomic ordering. The local structure formation of Cr23C6-type nanophase was confirmed by nanobeam electron diffraction. A development process of dense precipitates of the Cr23C6-type nanophase was further studied by high-resolution electron microscopy. It was found that the formation of the highly-dense nanoprecipitates provides an increase in Vickers hardness.
2077
Authors: M. Ishida, H. Takeda, Nobuyuki Nishiyama, Y. Shimizu, K. Kita, Yasunori Saotome, Akihisa Inoue
543
Authors: Qing Wang, Chun Lei Zhu, Yan Hui Li, Jiang Wu, Chuang Dong, Jian Bing Qiang, Wei Zhang, Akihisa Inoue
Abstract: The present paper investigates the bulk metallic glass formation in Co-based alloy systems with the guidance of the cluster line and minor-alloying principles. The selected basic ternary Co-B-Si alloy compositions are intersecting points of cluster lines, defined by linking special binary clusters to the third element. Then these basic ternary alloys are further minor-alloyed with Nb and quaternary bulk metallic glasses are obtained only by 4-5 at. % Nb minor-alloying of the basic composition Co68.6B25.7Si5.7 that is developed from dense-packed cluster Co8B3. The bulk metallic glasses are expressed approximately with a unified simple composition formula: (Co8B3)1(Si,Nb)1. In addition, a quantity of Fe substitution for Co further improves the glass-forming abilities.
1275
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