2003 Fiscal Year Final Research Report Summary
Evaluation of plastic working properties of fine grained aluminum alloy
| Project/Area Number |
14550689
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | Chiba Institute of Technology |
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Principal Investigator |
FUNAMI Kunio Chiba Inst. of Technology, Faculty of Engineering, Professor, 工学部, 教授 (90010876)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMIZU Hideharu Chiba Inst. of Technology, Faculty of Engineering, Research Assistant, 工学部, 助手 (30178983)
SUZUKI Kouji Chiba Inst. of Technology, Faculty of Engineering, Lecturer, 工学部, 講師 (70322427)
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| Project Period (FY) |
2002 – 2003
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| Keywords | fine-grained structure / heavy plastic deformation / dynamic re-crystallization / bi-axial tensile machine / superplsticity forming / structure inhomogeneity |
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| Research Abstract |
The purpose of this research is to improve and evaluate the plastic working properties and production process of material which overly has a fine grained structure using the warm multi-axial alternative forging (MAF) method which is one of some hard strain induced methods due to enhancement of the strength of aluminum alloy.
2002 * The invention of board material which has microstructure with sub micrometer grain size was able to achieve sufficient success according to the combination processing process of warm multi-axial alternative forging forge and rolling. * The bi-axial tension testing machine made as an experiment for evaluation of the plastic processing of material with fine grained stricture and it checked that this machine had accuracy sufficient as tensile testing machine with specification as following : (Load ; 5 kN and Stroke ; 120mm, Strain rate ; 10^<-5>〜10^3, Temperature ; 〜600℃, Shape of specimen ; cruciform). Moreover, the optimal form and size of cruciform specimen u
… More
sed were determined.
2003 * The produced cruciform specimens can give plastic deformation of 80% or more in conditions of bi-axial stress under high temperature deformation. * Although m value decreases with the increase in strain rate under uni-axial stress, that value maintains 0.30 or more to 1.7 x 10^<-1>s^<-1> which is high strain rate under bi-axial stress. * For same grain sized specimens, the difference of many mechanical characteristics appeared notably under uni-axial and bi-axial stress. In annealing temperature 673K in which the difference produced, n values were 0.33 and 0.26 under a uni-axial and bi-axial stress respectively. * The effect of grain size on mechanical properties is different for condition under uni-axial and bi-axial stress. * At experimental temperature 673K and strain rate 8.3 x 10^<-2>s^<-1>, the dynamic re-crystallization was checked also under bi-axial stress without shear deformation after changing about 60%. * Although a crystal grain develops in the tensile direction and voids arise perpendicularly to the tensile direction under uni-axial stress at temperature 673K,the shape of deformed grain maintains the situation of equiaxial distortion for bi-axial stress and voids produces to arbitrary directions.
Since the situation of deformation changes with loading stress states in the superplasticity deformation using fine grained material, it is necessary to use the work processing evaluation parameter under bi-axial stress in the deformation simulation for work processing condition presumption. Less
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