研究者詳細 - 多田　直哉

MISC - 多田　直哉

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研究のモチベーション査読

多田直哉

材料 62 ( 7 ) 472 - 472 2013年

924 巨視的ひずみ勾配下の周期境界条件に関する検討(OS9,OS10 合同ポスターセッション,OS・一般セッション講演)

内田真, 多田直哉

計算力学講演会講演論文集 2012 ( 25 ) 378 - 379 2012年10月

OS0302 温間二軸圧縮における初期等方性AZ31マグネシウム合金鋳造材の塑性変形と成形限界

平野聖記, 清水一郎, 秋山大輔, 多田直哉

M&M材料力学カンファレンス 2012 "OS0302 - 1"-"OS0302-2" 2012年9月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

Magnesium alloys have special features such as light weight, high specific strength and good reusability. However, information on the flow behavior and formability of magnesium alloys in multi-axial compressive stress conditions is highly limited, nevertheless of their importance for plastic working processes such as forging and extrusion. In the present study, the uniaxial and biaxial compression tests along proportional strain paths were conducted at room and at elevated temperatures, and thus the influence of strain paths and temperature upon mechanical properties and compressive forming limit were discussed. The results revealed that the flow stress scarcely changes with the test temperature in the range from 493 K to 523 K. On the other hand, the compressive forming limit was found to be dependent on the temperature as well as the strain paths.

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J041025 純チタン結晶粒内マイクロピラーの単軸圧縮変形の結晶方位依存性に関する基礎的検討

清水一郎, 岡野翔太朗, 多田直哉

年次大会 : Mechanical Engineering Congress, Japan 2012 "J041025 - 1"-"J041025-3" 2012年9月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

Titanium is one of materials with hexagonal close-packed structure, in which mechanical twinning often occurs and the plastic behavior becomes rather complicated. In recent years, the compression testing technique of a micropillar fablicated in a grain of metallic material has been developed for the purpose to study the deformation properties of a single crystal structure in a polycrystalline aggregate. In the present study, micropillars with rectangular cross section were fablicated in grains of industrial pure titanium by Focused Ion Beam (FIB) technique. The micro-compression tests were then performed in order to investigate the compressive behavior of single crystal micropillars. It was found that the load-displacement relations obtained by compression tests varied according to the crystal orientation and dimensions of the micropillars. Several traces of mechanical twinning were found to appear on the side surfaces of micropillars after the compression test, when the compressive force was applied in <0001> direction of the titanium grains.

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直流電位差法を用いた微小接合界面損傷の非破壊評価 (電界計測の応用とその新展開(2))

多田直哉

非破壊検査 61 ( 9 ) 452 - 457 2012年9月