2005 Fiscal Year Final Research Report Summary
Development of High Strength Metallic Materials Controlled for Nanostructure Using Severe Plastic Deformation
| Project/Area Number |
15360370
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
HORITA Zenji KYUSHU UNIVERSITY, Faculty of Engineering, Professor, 工学研究院, 教授 (20173643)
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| Co-Investigator(Kenkyū-buntansha) |
KANEKO Kenji KYUSHU UNIVERSITY, Faculty of Engineering, Associate Professor, 工学研究院, 助教授 (30336002)
NAKAMURA Katsuaki KYUSHU UNIVERSITY, Faculty of Engineering, Research Associate, 工学研究院, 助手 (70363380)
HISATSUNE Yoshimi KYUSHU UNIVERSITY, Faculty of Engineering, Research Associate, 工学研究院, 助手 (60380581)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Severe plastidc deformation / Torsion strain / Mg alloys / Al alloys / Ultrafine grain / Tensile testing / Superplasticity / Age hardening |
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| Research Abstract |
(1)In this study, a facility for high pressure torsion (HPT) was established in order to impose severe plastic deformation (SPD) on metallic materials under high pressure. This facility permits use of disk-type and cylindrical type of specimens at elevated temperatures for the former type of specimens.
(2)HPT was conducted on an Al-3%Mg-0.2%Sc alloy. The effect of rotation and imposed pressure on the hardness and microstructure was examined for both types of specimens. The hardness increased with an increase in rotation and applied pressure but there was a saturation of both types of specimens. The grain size was reduced to 0.15 μm at the outer edges of the specimens. Tensile tests at high temperatures revealed superplastic elongation, of 〜500% for the disk specimens and 〜1600% for the cylindrical specimens.
(3)HPT at 150℃ for Mg alloys showed that the grain size was reduced from 22 μm to 0.22 μm which then resulted in a superplastic elongation of 〜620% at 200℃ with a strain rate of 3.3x10^<-3> s^<-1>.
(4)A carbon steel processed by HPT exhibited an significant increase in hardness at outer edges of the disk specimens. This trend was different from Al alloys and Mg alloys. Tensile strength of 1.2 GPa was attained from the HPT specimens.
(5)Age-hardenable Al alloys were subjected to SPD through equal-channel angular pressing (ECA). Aging at 100℃ for the ECAP processed alloys led to an increase in hardness and also an increase in uniform elongation There was a great potential for an increase in both strength and ductility when SPD specimens are subjected to aging treatment at lower temperatures.
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Research Products
(33 results)
