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STRUCTURE AND NATURE OF VERY SMALL POINT DEFECT CLUSTERS STUDIES BY POSITRON LIFETIME AND TRANSMISSION ELECTRON MICROSCOPE

Research Project

Project/Area Number 10650650
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Physical properties of metals
Research InstitutionHIROSHIMA UNIVERSITY

Principal Investigator

FUKUSHIMA Hiroshi  Faculty of Engineering, HIROSHIMA UNIVERSITY, Associate Professor, 工学部, 助教授 (70156769)

Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥3,000,000 (Direct Cost: ¥3,000,000)
KeywordsPositron Annihilation / Transmission Electron Microscopy / Lattice Defects / Point Defect Clusters / Radiation Damage / Low Teperature Irradiation / Displacement Cascade / 透過型電子顕微鏡法
Research Abstract

It has been concluded that we can obtain reliable and new information about very small point defect clusters using both positron lifetime measurement and transmission electron microscopy (TEM) technique. TEM observation has analyzed the local structure of defect clusters, and positron lifetime measurement has detected small vacancy clusters whose size is smaller than the TEM resolution. The size of three dimensional vacancy clusters produced by displacement cascades in Cu and Si is smaller than divacancies, and the larger vacancy clusters collapse to stacking fault tetrahedra (SPT) and dislocation loops.
Weak-beam dark-field (WBDF) method has been applied to identify the very small point defect clusters of vacancy-type and interstitial-type by TEM images. Systematic change of image-size has been examined for dislocation loops whose sizes are between 1 nm and 2 nm by systematically changing a deviation parameter from the Bragg condition. Nature of dislocation loops has been determined by measuring the change in size of the dislocation loops in Cu irradiated with 600 keV self-ions at 20 K and that after 120 K anneal at which temperature all the single interstitial atoms have already moved to dislocation loops and their sinks. Both vacancy and interstitial types are observed, but systematic change of sizes for each type of loops has been hardly observed. Further work using computer image-simulation is needed.
Positron lifetime at SFT site has been determined, but is close to that at a vacancy site. Positron lifetime method has been able to evaluate the decrease in dislocation loop density, but has not been able to separate the effects of vacancy and interstitial types. Stereo measurement using TEM has disclosed the difference between the spatial distribution of vacancy-type defect clusters and that of interstitial-type defect clusters for the first time.

Report

(3 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] H.Fukushima, K.Ochial and Y.Shimomura: "Voids in Fast-Neutron-Irradiated Cu,Ni and Cu-Ni Concentrated Alloys Studied by TEM and Positron Annihilation Methods"Journal of Nuclear Materials. 271 & 272. 220-224 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.L.Jenkins,M.A.Kirk and H.Fukushima: "On the Application of the Weak-Beam Technique to the Determination of the Sizes of Small Point-Defect Clusters in Ion-Irradiated Copper"Journal of Electron Microscopy. 48. 323-332 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.A.Kirk,M.L.Jenkins and H.Fukushima: "The Search for Interstitial Dislocation Loops Produced in Displacement Cascades at 20K in Copper"Materials Reseaarch Society Symposium Proceedings. 540. 521-526 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.A.Kirk,M.L.Jenkins and H.Fukushima: "The Search for Interstitial Dislocation Loops Produced in Displacement Cascades at 20K in Copper"Journal of Nuclear Materials. 276. 50-58 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] 福島博: "透過電子顕微鏡法による変位カスケードの研究"まてりあ(日本金属学会). 40(印刷中). (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] H. Fukushima, K. Ochiai and Y. Shimomura: "Voids in Fast-Neutron-Irradiated Cu, Ni and Cu-Ni Concentrated Alloys Studied by TEM and Positron Annihilation Methods"J.Nucl.Mater.. 271&272. 220-224 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M. L. Jenkins, M. A. Kirk and H. Fukushima: "On the Application of the Weak-Beam Technique to the Determination of the Sizes of Small Point-Defect Clusters in Ion-Irradiated Copper"J.Electron Micros.. 48. 323-332 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M. A. Kirk, M. L. Jenkins and H. Fukushima: "The Search for Interstitial Dislocation Loops Produced in Displacement Cascades at 20K in Copper"Mater.Res.Soc.Symp.Proc.. 540. 521-526 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M. A. Kirk, M. L. Jenkins and H. Fukushima: "The Search for Interstitial Dislocation Loops Produced in Displacement Cascades at 20K in Copper"J.Nucl.Mater.. 276. 50-58 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] H. Fukushima: "Transmission electron microscopy studies of displacement cascades"'MATERIA' (Japan Inst.Met.). 39,(in press). (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.L.Jenkins,: "On the Application of the Weak-Beam Technique to the Determination of the Sizes of Small Point-Defect Clusters in Ion-Irradiated Copper"Journal of Electron Microscopy. 43・4. 323-332 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] M.A.Kirk,: "The Search for Interstitial Dislocation Loops Produced in Displacement Cascades at 20K in Copper"Journal of Nuclear Materials. 276. 50-58 (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] 福島博: "カスケード損傷欠陥と透過電子顕微鏡法"まてりあ. (in press). (2000)

    • Related Report
      1999 Annual Research Report
  • [Publications] M.A.Kirk: "The Search for Interstitial Dislocation Loops Produced in Displacement Cascades at 20K in Copper" Journal of Nuclear Materials. in press. (1999)

    • Related Report
      1998 Annual Research Report
  • [Publications] M.L.Jenkins: "On the Application of the Weak-Beam Technique to the Determination of the Sizes of Small Point-Defect Clusters in Ion-Irradiated Copper" Journal of Electron Microscopy. in press. (1999)

    • Related Report
      1998 Annual Research Report

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Published: 1998-04-01   Modified: 2016-04-21  

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