日本語
NIHON UNIVERSITY's 
College of Engineering 
General Educations 

Updated : 2019/07/12 
Associate Professor 
Takagi Hidenari 

Birth:1978  
Tel.024-956-8694  
 
My website is here.  

Career (Number of the published data : 3)
日本大学工学部ポスト・ドクター  2005/04-2006/03 
日本大学工学部総合教育物理学教室助手  2006/04-2010/03 
日本大学工学部総合教育物理学教室専任講師  2010/04-Present 

Academic background (Number of the published data : 1)
Nihon University  Graduate School, Division of Engineering  機械工学専攻  Doctor later  Domestic 

Current state of research and teaching activities
Indentation creep tests were performed on an Al-5.3 mol% Mg solid-solution alloy to examine whether mechanical properties can be extracted accurately from a testpiece, as small as a rice grain. A conical and diamond indenter was pressed into a test surface with a constant load at temperatures ranging from 546 K to 590 K. When the representative flow stress and the indentation strain rate in the underlying material decreases to each critical value of critical stress and critical strain rate, as indentation creep proceeds, the stress exponent for creep varies distinctively from 4.9 to 3.0. The measured critical stress decreases with increasing temperature, while the corresponding indentation strain rate increases under the same condition. This temperature dependence is in close agreement with the results derived from the dislocation theory. The activation energy for creep in range M is approximately equivalent to that for the lattice diffusion of pure aluminum, and the value in range A is close to that for the mutual diffusion of this alloy. With load-jump tests, the indentation load was abruptly increased in the indentation creep test. In range M, instantaneous plastic deformation (IPD) takes place evidently even with a slight abrupt increase in load. On the other hand, the IPD does not occur in range A when load increment is within a certain value. However, the occurrence of IPD is observed under the special condition. The findings suggest that the creep rate-controlling process changes from the recovery control to the glide control below critical stress. It is thus demonstrated that the indentation testing technique can be effectively used to extract material parameters equivalent to those obtained from conventional uniaxial creep tests in the dislocation creep regime. 

Research Areas (Number of the published data : 2)
Metallic Physical Properties 
Structural/Functional materials 

Research keywords (Number of the published data : 3)
Creep Characterization of metals using indentation technique 
高温力学特性 
軽金属 

Subject of research (Number of the published data : 4)
一定応力押込みクリープ試験による微細結晶粒5083アルミニウム合金の応力指数の測定  2006-Present 
長周期積層構造相を有するマグネシウム合金における高温力学特性評価  2007-Present 
インデンテーション法を用いた活性化体積評価法の確立  2007-Present 
計装化押込み試験法を用いた超微細結晶粒を有する構造材料の力学特性評価  2010/04-Present 
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Proposed theme of joint or funded research (Number of the published data : 1)
インデンテーション法を用いた新しい力学特性を評価するための基礎研究 
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Bibliography (Number of the published data : 1)
工学系の物理学実験  学術図書出版社  2009/03 
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Papers (Number of the published data : 21)
High-temperature creep mechanism of dual-phase magnesium alloy with long-period stacking ordered phase  Materials Transactions  2019 
LPSO相を含む延性二相マグネシウム合金の高温クリープ機構  日本金属学会誌  2018/03/25 
Deformation behavior immediately after indentation load change in ultrafine-grained Al-Mg solid solution alloys  Journal of Materials Engineering and Performance  2016 
インデンテーション法による高温力学特性評価  日本材料試験技術  2015/05 
Set of conversion coefficients for extracting uniaxial creep data from pseudo-steady indentation creep test results  Materials Science and Engineering, A  2014 
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Research presentations (Number of the published data : 105)
Poster presentation  押込み試験によるAl-Mg合金の高温における活性化体積の評価  軽金属学会  2018 
Oral presentation(invited, special)  Mechanical Characterization at high temperature through instrumented indentation testing techniques  6th International Indentation Workshop  2018/07/05 
Oral presentation(general)  計装化押込み試験法による金属材料の力学挙動調査  日本材料科学会北海道東北支部 第1回材料科学コロキウム  2018/06/01 
Oral presentation(general)  計装化押込み試験法による活性化体積の評価  日本材料科学会北海道東北支部 第1回材料科学コロキウム  2018/06/01 
Oral presentation(general)  Mg基LPSO合金の高応力域における回復速度の測定  軽金属学会  2017 
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Prizes (Number of the published data : 2)
日本金属学会論文賞(力学特性部門)  2013/09/17  Domestic 
日本金属学会論文賞(力学特性部門)  2006/09/16  Domestic 
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Research expenses (Number of the published data : 21)
Donation  アルミニウム合金のクリープ領域における活性化体積の評価 
Donation  鉄鋼材料に関する高温強度 
Donation  鉄鋼材料に関する高温強度  2018/04-2019/03 
Donation  塑性加工が施されたLPSO型マグネシウム合金の力学特性評価  2018/04-2019/03 
Donation  塑性加工が施されたLPSO型マグネシウム合金の力学特性評価  2017/04-2018/03 
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Alloted class (Number of the published data : 3)
物理学I 
物理学II 
物理学実験及び演習 
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Memberships of academic societies (Number of the published data : 4)
日本金属学会 
日本鉄鋼協会 
軽金属学会 
日本機械学会 
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