Study of formation mechanism of point defect clusters produced in deformed fcc metal
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants|
Physical properties of metals
|Research Institution||Hiroshima Institute of Technology|
KOMATSU Masao Hiroshima Institute of Technology, Faculty of Engineering, Associate professor, 工学部, 助教授 (80309616)
|Project Period (FY)
2003 – 2004
Completed(Fiscal Year 2004)
|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 2004 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 2003 : ¥1,000,000 (Direct Cost : ¥1,000,000)
|Keywords||Point defect clusters / Stacking fault tetrahedra / Evaporated single crystal / Electron microscope / Plastic deformation / Dislocation|
Heavy plastic deformation of fcc metal thin foils to fracture has been found recently to proceed with involving dislocation, and it results in the formation of high density of vacancy clusters, so called stacking-fault tetrahedra (SFT). For investigation of formation process of the SFT, thin single crystal specimens of fcc metal such as Au and Ag were prepared using vacuum evaporation technique in the first year. The specimen thickness and the index of specimen surface were about 50 nm and (110), respectively. In the next year, these specimens were plastically deformed to fracture in in-situ elongation experiments under an electron microscope. The results are summarized as follows :
(1)SFTs produced during deformation of thin gold single crystal specimen were hardly formed with decreasing specimen thickness (<〜50 nm).
(2)High density of SFTs had formed on trace of (111) slip planes.
(3)Production speed of SFT was very high, therefore the rate could not measured in this experiment.
(4)The size of produced SFTs was extremely small, i.e. 2〜10 nm in diameter.
(5)Nature of all SFTs produced by plastic deformation were point defect clusters of vacancy type.
(6)It was confirmed that some of SFTs produced by plastic deformation easily disappeared by mutual interfere.
(7)In the specimen thickness was 〜70 nm, density of SFTs increased with increasing of dislocation density.
This study revealed about condition how SFTs were produced by elongation deformation of thin gold single crystal. But now, primary process of SFT production is not yet clear sufficiently in this study. In the next stage, it is necessary to carry out the same study at low temperature so that migration rate of vacancy becomes low.
Research Products (5results)