JaLCDOI 10.18926/15837
FullText URL Mem_Sch_Eng_OU_21_2_1.pdf
Author Takemoto Yoshito| Hida Moritaka|
Abstract We investigated the effects of resolved interstitial oxygen or nitrogen atoms and of quenched-in strain on the hardening of the single crystals grown from molten Ti-14 and 20wt pct Mo alloys. The aging treatment at 623K in atmosphere much more increased in the hardness of specimen surface than that in argon atmosphere. The quenched-in compressive stress enhanced age hardening due to omega formation. We surveyed in detail the hardness changes toward the center of plate-shaped single crystal.
Publication Title Memoirs of the School of Engineering, Okayama University
Published Date 1987-03-05
Volume volume21
Issue issue2
Start Page 1
End Page 7
ISSN 0475-0071
language 日本語
File Version publisher
NAID 120002307640
JaLCDOI 10.18926/15489
FullText URL Mem_Fac_Eng_OU_24_2_1.pdf
Author Umemoto, Masayuki| Takemoto, Yoshito| Sakakibara, Akira| Hida, Moritaka|
Abstract Fine particles of Ti-Mo alloy were prepared by evaporation. When Ti-40at % Mo alloy was evaporated on tungsten filament, fine particles of Ti contaminated with W were obtained. These particles were polyhedron in shape and 10~250nm in diameter. Average diameter and size distribution increased with pressure of argon gas (100~600 Torr). When pure Ti was placed on the Mo filament and evaporated from melt down of heated Mo filament in helium gas, fine particles of pure Ti and of Ti-Mo alloy were obtained. In this case, Ti particles were of indeterminate form and of several tens nm in diameter, and their diffraction pattern was of common α-Ti. On the other hand, composition of the Ti-Mo particles was determined to be 18at % Mo by an analysis of EDX. Structure of Ti-Mo particles could not be determined because their diameters were more than 600nm. The temperature of Mo filament, for the most part, was about 1800℃, and there pure Ti particles were produced. The temperature of the fused part of the filament was locally higher than 2600℃, and there Ti-Mo particles were produced. Fine structures of contact region among some Ti particles were observed with HRTEM.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1990-03-29
Volume volume24
Issue issue2
Start Page 1
End Page 9
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307765
JaLCDOI 10.18926/19589
FullText URL Mem_Fac_Eng_OU_31_2_11.pdf
Author Ishii Kouta| Takemoto, Yoshito| Hida, Moritaka|
Abstract Fine particles of Ti-V alloy were prepared by means of arc method and were investigated on internal structure and phase transformation using HR-TEM and EDS. Martensite phase was observed in a particle containing comparatively low concentration of V, and ω phase was also found to exist in a nearly 15% V particle. The structure of the ω phase in the fine particle is remarkably expanded in comparison with the bulk sample, and the ω phase is unstable, so that it has disappeared in a few seconds during TEM observation.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1997-03-28
Volume volume31
Issue issue2
Start Page 11
End Page 20
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309004
JaLCDOI 10.18926/15448
FullText URL Mem_Fac_Eng_OU_28_2_1.pdf
Author Takemoto, Yoshito| Sakakibara, Akira| Hida, Moritaka|
Abstract Fine particles of Ti-Mo alloy have been prepared by means of arc method, and investigated on internal structure and phase transformation using HR-TEM and EDS. Martensite phase was observed in a particle containing comparatively low concentration of Mo, and ω phase was also found to exist in a nearly 14 % M0 particle. The structure of the ω phase in the fine particle is expanded and remarkably unstable in comparison with the bulk sample, so that it has disappeared in a few seconds during TEM observation. Moreover, the β structure of Ti-Mo particles has changed to the unusual fcc phase with irradiation of a strong electron beam.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1994-03-15
Volume volume28
Issue issue2
Start Page 1
End Page 7
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307644
JaLCDOI 10.18926/15500
FullText URL Mem_Fac_Eng_OU_25_2_1.pdf
Author Okada, Hiroyuki| Hida, Moritaka| Sakakibara, Akira| Takemoto, Yoshito|
Abstract Tensile strength and elongation of cast magnesium reinforced with titanium fiber were measured by tensile test. The pull-out test of a titanium rod partially embedded in a magnesium matrix was performed to evaluate interfacial bonding strength between magnesium and titanium. It was found that when the fiber volume fraction was changed from 1% to 14%, the tensile strength was improved with increase of volume fraction, while the improvement of elongation tended to be restrained beyond the volume fraction of 10%. The interfacial strength was revealed to be strong, and this was substantiated by the scanning electron microscopy showing an excellent wettability between the titanium fiber and the magnesium matrix.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1991-03-28
Volume volume25
Issue issue2
Start Page 1
End Page 8
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307559
JaLCDOI 10.18926/19588
FullText URL Mem_Fac_Eng_OU_31_2_1.pdf
Author Arisawa Hideaki| Song Zhi-Yi| Takemoto, Yoshito| Hida, Moritaka|
Abstract The microstructure of oxidizing magnesium at elevated temperatures has been studied using HR-TEM, SEM and EDS. Two kinds of thin magnesium specimen for TEM observation were prepared. One was oxidized after preparing TEM foil of magnesium, the other was prepared from an oxidized bulk magnesium for observing the cross-section of oxide/Mg interfacial region. In the former, several oxides(MgO) morphologies were observed depending on the temperature and time of the oxidization. The growth of needle-like oxides formed at 573K and mottled oxides formed at 773K were recognized as a remarkable phenomenon belonging to the local oxidization. These oxides were composed of poly-crystal. The thin uniform oxidization layer was also observed in all conditions. In the cross-sectional observation, the local oxide layer, nearly 300nm in thickness, on the matrix(Mg) were observed. The thin uniform oxidized layer of bulk samples was identified as a kind of modified layer (~40nm in thickness) in which the formation of HR-TEM lattice fringes were prevented by the strain due to the slight oxidization.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1997-03-28
Volume volume31
Issue issue2
Start Page 1
End Page 10
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309082
JaLCDOI 10.18926/15397
FullText URL Mem_Fac_Eng_OU_30_2_1.pdf
Author Takemoto, Yoshito| Hida, Moritaka| Sakakibara, Akira|
Abstract The mechanism of brittle fracture in Ti-14mass % Mo alloy aged for 1x10(6)s at 623K was studied using transmission electron microscopy (TEM) and dynamic hardness test (DHT) on the structure deformed by means of tensile elongation at elevated temperature or cold rolling. Many band products were observed by TEM in either deformed specimens. These band products were identified to neither slips nor twinning bands, moreover, they were different from α , α ' and α " phases. The band product consisted of β phase and granular unknown phase which was transformed by deformation from ω phase. The newly discovered phase, named β" phase, in the band products had a body-centered triclinic structure. The β" was similar to the ω zone with respect to the morphology and the concentration of Mo, but it resembled β in structure. The result of DHT on the band products and the matrix showed that the band products were softer than the matrix. It is suggested that the band products are easily deformed because of the disappearance of obstacles such as ω phase, and consequently behave like paths to lead cracks preferentially.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1996-03-29
Volume volume30
Issue issue2
Start Page 1
End Page 7
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307225
JaLCDOI 10.18926/19648
FullText URL Mem_Fac_Eng_OU_33_2_1.pdf
Author Omura, Yasuhiro| Hida, Moritaka| Sakakibara, Akira| Takemoto, Yoshito|
Abstract Molecular dynamics simulation of nickel crystal under uniaxial tensile and compressive deformation was performed for single nenocrystal model and twinned nanocrystal model composed of 1550 atoms using EAM (embedded atom method) potential with the object of investigating deformation induced phase tranformation (especially twin deformation). In the case of single nanocrystal model, the evolution and development of twin deformation, (111)[11(2)], is observed under compressive loading in [001] direction, whereas either slip or twin deformation is not recognized under tensile loading. In the case of twinned nanocrystal model, twin, (111)[11(2)], decreases and disappears under tensile loading, and develops under compressive loading, It is suggested from the difference of results between single nanocrystal model and twinned nanocrystal model that it is easy for twin to induce local deformation.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1999-04-27
Volume volume33
Issue issue2
Start Page 1
End Page 8
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309020
Author Muraoka, Yuji| Yoshii, Fumiya| Fukuda, Takahiro| Manabe, Yuji| Yasuno, Mikiko| Takemoto, Yoshito| Terashima, Kensei| Wakita, Takanori| Yokoya, Takayoshi|
Keywords Strain effect Spinodal decomposition Titanium dioxide Vanadium dioxide Thin films Interdiffusion Nanostructure Pulsed laser deposition
Note This fulltext is available in Feb 2022|
Published Date 2020-03
Publication Title Thin Solid Films
Volume volume698
Publisher Elsevier
Start Page 137854
ISSN 0040-6090
NCID AA00863068
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
File Version author
DOI 10.1016/j.tsf.2020.137854
Web of Science KeyUT 000521128800021
Related Url isVersionOf https://doi.org/10.1016/j.tsf.2020.137854
JaLCDOI 10.18926/15453
FullText URL Mem_Fac_Eng_OU_28_2_13.pdf
Author Kusumoto, Hisao| Hida, Moritaka| Sakakibara, Akira| Nishida, Norihide| Takemoto, Yoshito| Yamada, Masuo|
Abstract The strain in Si substrate induced by locally ion-plated thin film of TiN was observed by X-ray topograph (Lang technique). Circular TiN film was deposited on one side of the Si surface. In all topographs the highest blackness attributed to kinematical diffraction effect occurred at the film edge. Rosette pattern with four-lobes was observed around the film. Blackness as a whole increased with the film thickness. Strain was observed in the depth direction of substrate by limited projection method. When the slit width was narrowed, the kinematical images disappeared, and white images appeared at the film edge. All the contrast disappeared when the TiN film was completely removed in boiling HNO(3). The strain induced by the film deposition was proved to be elastic.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1994-03-15
Volume volume28
Issue issue2
Start Page 13
End Page 20
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307150
Author 竹元 嘉利|
Published Date 1997-09-30
Publication Title
Content Type Thesis or Dissertation