Korean Journal of Metals and Materials (대한금속재료학회지)

The Korean Institute of Metals and Materials (대한금속재료학회)
권호 표지

Dynamic Deformation Behavior of Ultra-Fine-Grained Pure Coppers Fabricated by Equal Channel Angular Pressing

ECAP으로 제조된 초미세립 순동의 동적 변형거동

  • Kim, Yang Gon (Center for Advanced Aerospace Materials Pohang University of Science and Technology) ;
  • Hwang, Byoungchul (Ferrous Alloys Research Group Korea Institute of Materials Science) ;
  • Lee, Sunghak (Center for Advanced Aerospace Materials Pohang University of Science and Technology) ;
  • Lee, Chul Won (Ferrous Alloys Research Group Korea Institute of Materials Science) ;
  • Shin, Dong Hyuk (Department of Metallurgy and Materials Science Hangyang University)
  • 김양곤 (포항공과대학교 항공재료연구센터) ;
  • 황병철 (한국기계연구원 부설 재료연구소 철강재료연구그룹) ;
  • 이성학 (포항공과대학교 항공재료연구센터) ;
  • 이철원 (한국기계연구원 부설 재료연구소 철강재료연구그룹) ;
  • 신동혁 (한양대학교 금속재료공학과)
  • Received : 2008.01.22
  • Published : 2008.09.25
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Abstract

Dynamic deformation behavior of ultra-fine-grained pure coppers fabricated by equal channel angular pressing (ECAP) was investigated in this study. Dynamic torsional tests were conducted on four copper specimens using a torsional Kolsky bar, and then the test data were analyzed by their microstructures and tensile properties. The 1-pass ECAP'ed specimen consisted of fine dislocation cell structures elongated along the ECAP direction, which were changed to very fine, equiaxed subgrains of 300~400 nm in size as the pass number increased. The dynamic torsional test results indicated that maximum shear stress increased with increasing ECAP pass number. Adiabatic shear bands were not found at the gage center of the dynamically deformed torsional specimen of the 1- or 4-pass ECAP'ed specimen, while some weak bands were observed in the 8-pass ECAP'ed specimen. These findings suggested that the grain refinement according to the ECAP was very effective in strengthening of pure coppers, and that ECAP'ed coppers could be used without serious reduction in fracture resistance under dynamic torsional loading as adiabatic shear bands were hardly formed.

Keywords

Acknowledgement

Supported by : 과학기술부, 산업자원부

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