Abstract ▼

The contents of of this research can be divided by three main topics; the scope of copper alloys, accumulation of high deformation energy, the practical application of nano-grained copper alloys. The highly alloyed copper is currently the most widely used high-strength connector material with the te

The contents of of this research can be divided by three main topics; the scope of copper alloys, accumulation of high deformation energy, the practical application of nano-grained copper alloys. The highly alloyed copper is currently the most widely used high-strength connector material with the tensile strength level ranging from 600 MPa to 800 MPa. The alloyed Cu, however, possesses inherently lower electrical conductivity compared to the unalloyed counterpart, such that the electrical conductivity values for the commercially available high-strength connector materials are, for exarnppe, only in the range of 10-15 %IACS (International Annealed Copper Standard). In order to overcome this inherent shortcoming associated with the conventional Cu alloys, the development of pure Cu with the nano-sized grains has been being explored by employing a severe plastic deformation principle. In this research, 99.99% pure oxygen-free copper and phosphorous-deoxidized copper (O.02wt. % P contained) were investigated. For practical applications, Cu composites and commercial copper alloy (PMC90) were also studied. Generally, strength of metal can be increased by the grain size refinement. In case of copper alloys, many thermo-mechanical treatment has been developed. The core of TMT process is to increase strength of copper alloys by the accumulation of large deformation energy, introduction of many small dispersoid as nucleation site for recrystallization and optimum heat treatment to form fine recrystallized grain. Recently, in order to accumulate high deformation energy, unique deformation processes have been developed such as Equal Channel Angular Pressing(ECAP), Cryogenic Rolling and! or Forging, Accumulative Roll Bonding(ARB) etc., which enable to get ultra-fine grained materials by in situ recrystallization. We adopted these processes to maximize deformation stored energy. Typical parts of applicaions of nano-grained copper alloys are electrical and electronic industires those require high strength and high electical conductivity compared to conventional alloys. On these purpose, we wiIl study on following sub application topics;
1) Welding electrodes
2) High-strength high-conductivity connectors
3) High-strength high-conductivity leadfrarnes
Generally, strength of metal can be increased by the grain size refinement. Ultra fine recrystalline grain can be acquired by proper hot working and heat treatment for high deformed material. Because fine grains are undtale at high temperature, it is necessary to inhibit growing of sub cell by homogeneous formation of fine particles. We developed grain refining technology for high deformed materials by not only controling of recovery and recrystallization but also introduction of fine second strengthening particles to prepare precipitation site of recrystallined grain and investgation of their recrystallization
mechanism.

목차 Contents

• 표지 ...1
• 제출문 ...2
• 보고서 초록 ...3
• 요약문 ...4
• SUMMARY ...9
• CONTENTS ...13
• 목차 ...15
• 제1장 연구개발과제의 개요 ...17
• 제1절 연구개발의 목적 ...17
• 제2절 연구개발의 필요성 ...17
• 제3절 연구개발의 범위 ...19
• 제2장 국내외 기술개발 현황 ...23
• 제1절 국내 기술개발 현황 ...23
• 제2절 국외 기 술개 발 현황 ...23
• 제3장 연구개발수행 내용 및 결과 ...25
• 제1절 강소성 가공기술 ...25
• 제2절 구속전단가공 (ECAP) 법에 의한 결정립 나노화 기술 ...31
• 제3절 반복겹침접합압연 (ARB)볍에 의한 결정립 나노화 기술 ...54
• 제4절 반복주름암연(RCS) 볍에 의한 결정 립 초미세화 기술 ...134
• 제5절 강소성 가공에 의 한 열축적 량 분석 ...159
• 제6절 강소성 가공된 동합금의 기 계 적 특성 ...165
• 제6절 나노 결정 립 통합금의 상용화 ...220
• 제4장 목표달성도 및 관련분야에의 기여도 ...224
• 제1절 연구개발의 목표달성도 ...224
• 제2절 관련분야에의 기여도 ...225
• 제3절 연구성과 총괄표 ...226
• 제5장 연구개 발결과의 활용계 획 ...227
• 1. 강소성 가공기술 ...227
• 2. 상용화 기술 ...227
• 제6장 연구개발과정에서 수집한 해외과학기술정보 ...228
• 제7장 참고문헌 ...229