研究者詳細 - 多田　直哉

K-0414 多結晶鋼の塑性変形に伴う結晶方位の観察(G03-4 静的強度)(G03 材料力学部門一般講演)

近藤了嗣, 阿部武治, 多田直哉, 清水一郎

年次大会講演論文集 1 107 - 108 2001年

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

Nonuniform deformation of each grain occurs in the plastic deformation of polycrystalline materials. Accordingly, it is necessary to clarity the behavior of deformation of each grain. The characteristics of each grain that constitutes polycrystalline material varies depending on grain orientation. So it is necessary to pay attention to the difference of grain orientation and the effective measurment technique which throw light on complicated grain deformation. In this paper, automatic measurement using electron backscatter difraction techinque in the scanning electronic maicroscope is performed, and the attention is paid on the grain orientation during plastic deformation to analyze relationship between orientation and plastic deformation.

DOI： 10.1299/jsmemecjo.I.01.1.0_107

604 連続転位分布を用いた粒界クリープ・キャビティの先端近傍応力場に関する数値解析

多田直哉, 大谷隆一, 生田裕也

学術講演会講演論文集 50 149 - 150 2001年

K-0530 Ni基単結晶超合金CMSX-2の高温疲労強度(S04-4 非鉄金属の組織と疲労特性)(S04 金属材料の組織と疲労強度信頼性)

大谷隆一, 多田直哉, 和田淳秀

年次大会講演論文集 1 185 - 186 2001年

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

A nickel-based single-crystalline superalloy, CMSX-2 was investigated from the standpoint of high temperature fatigue strength. Three kinds of push-pull fatigue tests were conducted at 1000℃: (1) PP-test under a sinusoidal stress waveform of 1 Hz-frequency at stress amplitude of 300MPa, the number of cycles to rupture, N_f=8,234, (2) CC-test under a trapezoidal one with hold time in tension and compression of 600s each at stress amplitude of 250MPa, N_f=93, and (3) PP_<preCC>-test, which is PP-test carried out after removal of surface oxide film and small cracks generating during preceding CC-test for 47 cycles, N_f=4,318. A distinguished microstructural difference between PP and PP_<preCC> is that γ'-phase kept the initial cubic shape in PP but it changed to spherical in PP_<preCC>-Nearly 10%-increase in total strain range and 50%-decrease in fatigue life of PP_<preCC> as compared with pure PP-fatigue is attributable to the collapse of γ'-phase.

DOI： 10.1299/jsmemecjo.I.01.1.0_185

K-0719 超微小硬度計によるアルミニウムの微視的変形挙動の観察(G03-3 ナノインデンテーション)(G03 材料力学部門一般講演)

坪井智昭, 阿部武治, 多田直哉, 清水一郎

年次大会講演論文集 1 327 - 328 2001年

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

It is well-known that the hardness of material is related to its mechanical characteristics. In the present study, the evaluation of the microscopic inhomogeneity of polycrystalline pure aluminum is performed by measuring the hardness of respective grains with the recently developed ultra-micro hardness tester. The relationship between the increase in the hardness caused by the work-hardening of the metal and the deformation of respective grains are studied.

DOI： 10.1299/jsmemecjo.I.01.1.0_327

K-0415 多結晶金属の塑性変形に伴う微視的変形挙動の観察(G03-4 静的強度)(G03 材料力学部門一般講演)

宋華林, 阿部武治, 清水一郎, 多田直哉

年次大会講演論文集 1 109 - 110 2001年

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

The surface roughening is closely related to the inhomogeneity of polycrystalline metals, that is, to the inhomogeneous plastic deformation of respective grains. In the present study, inhomogeneous deformation on the free surface of polycrystalline aluminum during uniaxial tension is studied. The inhomogeneous deformation of grains, which is represented by the area of the grain and the grain boundary length in the free surface, is observed by means of the laser-scanning microscope as a nondestructive method. Discussions are made mainly on the evaluation of inhomogeneous deformation of respective grains in polycrystalline aggregate.

DOI： 10.1299/jsmemecjo.I.01.1.0_109