ZK60A 마그네슘 합금의 압출 조건에 따른 석출상 형태의 변화
Evolution of precipitate morphology by extrusion condition in Mg ZK60A alloy
- 발행기관 아주대학교
- 지도교수 안병민
- 발행년도 2015
- 학위수여년월 2015. 2
- 학위명 석사
- 학과 및 전공 일반대학원 에너지시스템학과
- 실제URI http://www.dcollection.net/handler/ajou/000000018887
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
최근 환경,에너지 문제로 인해 이산화탄소 배출을 줄이기 위한 수송기 기 연비 향상 효율에 관심이 집중되고 있다.연비 향상을 위해서는 소재 의 경량화가 요구되는데,경량화 소재로서 마그네슘의 적용범위가 넓어지 고 그 수요 또한 증가하고 있다.마그네슘 합금은 상용 합금 중 최적의 경량소재로서,우수한 주조성 및 비강도 뿐 아니라 자원이 풍부한 장점이 있어 알루미늄을 대체할 경량소재로 많은 연구가 진행되고 있다. 그러나 마그네슘 합금은 HCP 구조로 인해 상온에서 성형이 어렵고,알 루미늄 합금에 비해 강도가 낮은 단점이 있으나 고온에서 압출,단조 등 의 공정을 통해 합금의 강도를 향상시킬 수 있다. 본 연구에서는 마그네슘 ZK60A 합금 연속 주조재를 6:1과 10:1의 압출 비로 압출해 압출 영향에 따른 석출상의 변화를 관찰하였다.EBSD를 이 용하여 grain structure 및 grain misorientation 분포 등을 분석하고, TEM,EDS 분석을 통해 압출 전/후 석출상의 거동을 분석하였다.
more목차
차례(TableofContents)
초록(Abstract)··································································ⅳ
그림차례(ListofFigures)·····················································ⅴ
표 차례(ListofTables)·······················································ⅵ
1.서론 ·············································································1
2.이론적 배경 ····································································2
2.1.마그네슘 합금의 일반적인 특성 및 동향 ·······························2
2.1.1.마그네슘 합금의 최근 동향 ···········································2
2.1.2.전자파 차폐성 우수 ····················································3
2.1.3.구조적 특성 ······························································3
2.2.ZK60A 합금의 조성 및 첨가 원소의 영향 ·····························6
2.3.마그네슘 합금 압출재의 강화기구 ······································10
2.3.1.가공 경화 ·······························································10
2.3.1.1.정의 ··································································10
2.3.1.2.Hall-Petchequation···············································10
2.3.1.3.Slipsystem ························································11
2.3.1.4.마그네슘 합금의 쌍정 변형 ·······································15
2.3.2.고용 강화 ·······························································17
2.3.3.석출 경화 ·······························································17
2.3.3.1.석출상에 의한 강화 메커니즘 ····································17
2.3.3.2.석출상 생성 메커니즘 ·············································18
2.3.3.3.마그네슘 합금 압출재의 석출상 생성 메커니즘 ···············23
3.실험 방법 ····································································25
3.1.압출 공정 ··································································25
3.2.성분 분석 ··································································27
3.2.1.ICP 분석 ································································27
3.2.2.X-RayDiffraction(XRD)분석 ·······································29
3.3.미세조직 분석 ·····························································31
3.3.1.ElectronBackScatteredDiffraction(EBSD)분석 ·················31
3.3.2.TransmissionElectronMicroscope(TEM)분석 ··················33
4.결과 및 고찰 ·································································35
4.1.마그네슘 합금 압출재의 성분 분석 ····································35
4.1.1.ICP 분석 ································································35
4.1.2.XRD 분석 ······························································38
4.2.마그네슘 합금 압출재의 미세조직 분석 ·······························40
4.2.1.EBSD 분석 ·····························································40
4.2.2.TEM 분석 ······························································45
4.2.2.1.입계 석출상 ·························································45
4.2.2.2.입내 석출상 ·························································51
4.2.2.3.석출상의 EDS 분석 ················································54
4.2.2.4.석출상의 기지 내 orientation·····································56
5.결론 ···········································································58
참고문헌(Reference)····························································59
