• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Study on the dislocation emission around a crack tip by using high-voltage electron microscopy

Research Project

Project/Area Number 10650651
Research Category

Grant-in-Aid for Scientific Research (C)

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

Principal Investigator

HIGASHIDA Kenji  Kyushu Univ. Dept. Mater. Sci. Eng., Associate Professor, 工学研究科, 助教授 (70156561)

Co-Investigator(Kenkyū-buntansha) MORIKAWA Tatsuya  Kyushu Univ. Dept. Mater. Sci. Eng., Associate Professor, 工学研究科, 助手 (00274506)
ARAMAKI Masatoshi  Kyushu Univ. Dept. Mater. Sci. Eng., Research Associate, 工学研究科, 助手 (50175973)
ONODERA Ryuta  Kyushu Univ. Dept. Mater. Sci. Eng., Professor, 工学研究科, 教授 (40038021)
Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1999: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1998: ¥2,500,000 (Direct Cost: ¥2,500,000)
Keywordsfracture / crack / dislocation / HVEM
Research Abstract

Dislocation emission from a crack tip is most fundamental process to understand the toughening mechanism of crystalline materials. In the present study, dislocation emission from the tip of a crack in MgO thin crystals has been investigated based on the geometry of crack tip dislocations observed using high voltage electron microscope(HVEM). In-situ experiments in the HVEM using tensile holder were also made. The effect of crack tip shielding due to the dislocations was also calculated using 3-D Buekner-Rice weight function theory for crack-dislocation interaction.
Dislocation image analyses showed that dislocations ahead of the crack tip observed in the present study were almost right-handed(R-H)screw dislocations lying on the(011)plane, while in the crack wake many of the dislocations were left-handed(L-H)on the (011)plane. Formation of such dislocation configuration can be understood by the emission of dislocation loops from sources at a crack tip, where crack jogs, crack kinks and intersections of crack planes with free surfaces may act as significant sources for dislocation emission. 3-D stress analysis exhibits that the largest component of crack tip stress intensities induced is mode I shielding type, and that mode II component is not negligible in the present case, suggesting the induction of the crack tip shielding for the mixed stress modes of I and II through the dislocation emission from the sources indicated above.

Report

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

    (6 results)

All Other

All Publications (6 results)

  • [Publications] K. Higashida and N. Narita: "Crack dislocation interaction in ionic crystals with rock-salt structure"Int. Journal of Materials and Product Technology. 14. 259-271 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Higashida, N. Narita, S. Asano and R. Onodera: "Dislocation emission from a crack tip MgO thin crystals"Materials Science and Engineering A. (印刷中). (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Higashida and N. Narita: "Crack dislocation interaction in ionic crystals with rock-salt structure"Int. Journal of Materials and Product Technology. Vol.14,. 259-271 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Higashida, N. Narita, S. Asano and R. Onodera: "Dislocation emission from a crack tip in MgO thin crystals"Materials Science and Engineering A. (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K.Higashida and N.Narita: "Crack dislocation interaction in ionic crystals with rock-salt structure"Int. Journal of Materials and Product Technology. 14. 259-271 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] K.Higashida, N.Narita, S.Asano and R.Onodera: "Dislocation emission from a crack tip in MgO thin crystals"Materials Science and Engineering A. (印刷中). (2000)

    • Related Report
      1999 Annual Research Report

URL: 

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

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi