JaLCDOI 10.18926/19606
FullText URL Mem_Fac_Eng_OU_33_1_5.pdf
Author Abe, Takeji| Namikoshi Ryuji| Nagayama Noriyuki| Takano Yasuju|
Abstract The influence of the slip between the inclusion and the matrix during the plastic deformation of inhomogeneous material with elliptic inclusions is investigated. The material is assumed to be rigid-plastic. The boundary slip region is modeled by assuming lower yield stress for the thin boundary region than those of the inclusion and the matrix. The rigid-plastic finite element method is used for the numerical calculation under the plane strain condition. The effects of the aspect ratio of the inclusion, the yield stress of the boundary region, and the volume fraction of the inclusion on the deformation mode are studied. The patterns of the strain concentration and the averaged flow stress of the inhomogeneous material are also discussed. The results may be helpful for understanding creep or superplastic deformation of metals with inclusions.
Keywords Plasticity Composite Material Sliding Inclusions Rigid-Plastic Deformation Finite Element Method
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 1998-11-30
Volume volume33
Issue issue1
Start Page 5
End Page 17
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002309204
JaLCDOI 10.18926/15346
FullText URL Mem_Fac_Eng_OU_35_9.pdf
Author Abe, Takeji| Tsuboi, Tomoaki|
Abstract The evaluation of microscopic inhomogeneity of polycrystalline aluminum is performed by measuring the hardness in respective grains. The recently developed ultra-micro hardness tester is used and the effects of the test pattern, the indentation load and the indenting velocity are examined. Then, the relationship between the increase in the hardness caused by the work hardening and the deformation of respective grains are statistically investigated. The hardness testing mode in which the initial load is applied before the onset of measurement gives more stable results than the testing mode without the initial load. The test condition with the indentation load of 9.8mN and the indentation velocity of 0.2 μm/sec seems to be optimum and gives the least dispersion of the measured values in grains. It is shown that the hardness values of respective grains in polycrystalline aluminum as well as their dispersion increase with the applied plastic strain. Discussion is made on the microscopic deformation behavior of polycrystalline aluminum.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 9
End Page 19
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307825
JaLCDOI 10.18926/15344
FullText URL Mem_Fac_Eng_OU_35_1.pdf
Author Abe, Takeji| Hualin Song| Akagi Yasuo| Shimizu, Ichiro|
Abstract Free surface of polycrystalline metal becomes roughened after plastic deformation. 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 specimen during uniaxial tension is studied. The inhomogeneous deformation of grains in the central area of the free surface of specimen is observed by the laser scanning microscope, while the inhomogeneous deformation perpendicular to the surface is studied by the laser scanning microscope as well as the stylus measuring instrument. It is shown that the surface roughness and the strain of respective grains increase with the applied strain. Discussions are made on the change in the surface roughness, the strain in each grain and the slip-line angles with the applied strain.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2001-03-27
Volume volume35
Issue issue1-2
Start Page 1
End Page 8
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002307340
JaLCDOI 10.18926/14135
FullText URL Mem_Fac_Eng_39_1_7.pdf
Author Wang, Xiaoqun| Abe, Takeji| Tada, Naoya| Shimizu, Ichiro|
Abstract Roughening on free surface of polycrystalline metal during plastic deformation is closely related to the inhomogeneous deformation in the respective grain at the surface. Uniaxial tensile tests are carried out on annealed pure aluminum sheet specimens with various averaged grain sizes. The roughening is measured by a 3-dimensional stylus instrument to examine the roughness change in both sides of specimen surfaces at each strain. The irregularities on one side are reversed on the backside, when the averaged grain size is as large as the thickness of the specimen. Discussions are made on the relation between the surface shapes of both sides adopting the cross correlation factor. The strains of respective grains are also measured from the grain boundary shape before and after plastic deformation. There are some deviations in the strains of the grains and their standard deviation increases with the applied strain.
Publication Title Memoirs of the Faculty of Engineering, Okayama University
Published Date 2005-01
Volume volume39
Issue issue1
Start Page 7
End Page 15
ISSN 0475-0071
language 英語
File Version publisher
NAID 120002308149