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Kafe 바로가기주관연구기관 | 한국과학기술원 Seoul National University |
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연구책임자 | 박은수 |
참여연구자 | 장혜정 , 김준곤 , 김진우 , 이제인 , 류욱하 , 류채우 , 오현석 , 김진연 , 김완 , 김일환 , 김경준 , 김상준 , 이광엽 , 임종욱 , 박현정 |
보고서유형 | 1단계보고서 |
발행국가 | 대한민국 |
언어 | 한국어 |
발행년월 | 2016-05 |
과제시작연도 | 2015 |
주관부처 | 미래창조과학부 Ministry of Science, ICT and Future Planning |
등록번호 | TRKO201700009745 |
과제고유번호 | 1711025963 |
사업명 | 원자력기술개발사업 |
DB 구축일자 | 2017-10-28 |
키워드 | 하이엔트로피 합금.내화 금속.방사선 손상.자가 치유 거동.고온 안정성.원자력 신소재.High entropy alloy.Refractory metal.Irradiation damage.Self-healing effect.High temperature stability.Advanced nuclear material. |
DOI | https://doi.org/10.23000/TRKO201700009745 |
1. 기존의 원자력 소재가 적용 불가능한 가혹한 환경에서의 미래형 원자로 소재로 방사선 손상에 대해 자가치유 효과를 갖고 상온/고온 물성이 우수한 refractory 하이엔트로피 합금을 개발함.
2. 하이엔트로피 합금의 다양한 방사선 조사시험평가를 수행한 결과 기존 합금에 비해 결함의 형성 및 전파가 느리고 조사 저항성이 우수한 것을 확인함.
3. 보고된 하이엔트로피 합금의 원자단위 전산모사 결과들과 종합하여, 1.캐스케이드 회복 시간이 연장되고, 2.공공의 형성 및 성장이 방해되어, 3. 결함의 형성과 성장이 방해되는,
1. 기존의 원자력 소재가 적용 불가능한 가혹한 환경에서의 미래형 원자로 소재로 방사선 손상에 대해 자가치유 효과를 갖고 상온/고온 물성이 우수한 refractory 하이엔트로피 합금을 개발함.
2. 하이엔트로피 합금의 다양한 방사선 조사시험평가를 수행한 결과 기존 합금에 비해 결함의 형성 및 전파가 느리고 조사 저항성이 우수한 것을 확인함.
3. 보고된 하이엔트로피 합금의 원자단위 전산모사 결과들과 종합하여, 1.캐스케이드 회복 시간이 연장되고, 2.공공의 형성 및 성장이 방해되어, 3. 결함의 형성과 성장이 방해되는, 하이엔트로피 합금에서의 독특한 자가치유 효과 메커니즘을 제시함.
4. 젓성자흡수단면적, 혼합엔탈피, BCC 상 형성을 기준으로 Al, Ti, V, Zr, Nb, Mo을 선택하여 4단계, 60여종의 합금개발을 거쳐 우수한 상온/고온 기계적 특성을 갖는 refractory 하이엔트로피 합금을 개발함.
5. 고온 기계적 특성 및 내산화성을 획기적으로 향상시키기 위한 후속 연구 방향으로 ODS 합금화, 초합금화 및 Silicide 부동태 피막 형성 연구를 제안함.
(출처: 보고서 요약서 4p)
Ⅲ. Research Results
• High entropy alloys showed lower defect concentration after high pressure torsion. For the phase stability of high entropy alloy, high temperature phase was stabilized after high pressure torsion. Both phenomena could be explained by sluggish diffusion aspect, which is consi
Ⅲ. Research Results
• High entropy alloys showed lower defect concentration after high pressure torsion. For the phase stability of high entropy alloy, high temperature phase was stabilized after high pressure torsion. Both phenomena could be explained by sluggish diffusion aspect, which is consistent to the atomic level stress concept suggested as the origin of self healing behavior of high entropy alloy.
• New transition metal based high entropy alloy with twin induced plasticity without losing strength was developed by considering solid solution hardening and stacking fault energy.
• New refractory high entropy alloys were developed by considering neutron absorption area, formation enthalpy and tendency to form bcc crystal structure.
• The refractory high entropy alloy showed both of good ductility and high strength in the composition range of Al-5at%, 10at%
• Microstructure and Phase transition mechanism analysis of high entropy alloy
- High entropy alloy is well known to have single solid solution phase, however most of high entropy has more than 2 types of solid solution or compositional segregation.
- After heat treatment, CrFeCoNi high entropy phase maintain its composition and micro structure at room temperature condition.
- During homogenization process, CrFeCoNi/Cu high entropy alloy precipitates various size and shape FCC particle due to element redistribution and stress relaxation.
- Calcuation of metastable phase diagram for CrFeCoNi/Cu high entropy alloy shows miscibility gap between CrFeCoNi and Cu which lead to solidification and phase separation during heat treatment.
• Appraisal of radiation damage under heavy ion irradiation
- Establishment of computer simulation system based on SRIM which can calculate irradiation affected region, irradiation damage and distribution of residual ion.
- Development of heating stage for high temperature irradiation
- Construction EBSD-FIB TEM sampling method for defect movement analysis at specific grain direction.
- CrFeCoNi high entropy phase shows superior phase stability under Cu ion irradiation at room temperature condition
- After Cu ion irradiation, Cu solid solution region has swelling behavior and evolution of porous surface and deeper recrystallization region at beneath the surface
- CrFeCoNi high entropy phase has very swallow recrystallization and no swelling and porous surface.
- Mechanical property test by nanoindenter and microindenter show irradiation hardening effect. Nanoindentation hardness data present hardening effect is related to temperature increasement. microindentation data shows irradiation hardening effect depending on radiation damage at room temperature. However at high temperature, 1 dpa radiation damaged sample and 10 dpa radiation damaged sample showed similar hardness result.
• Appraisal of radiation damage under proton irradiation
- Predition of proton irradiation region by SRIM is very narrow region and very few radiation damage near surface area.
- CrFeCoNi high entropy phase also has superior radiation resistibility under proton irradiation environment.
- After proton irradiation, Cu solid solution region has local swelling and recrystallization behavior
- CrFeCoNi high entropy phase has no significant surface morphogy evolution and recrystallization behavior.l
- Nanoindentation and microindentation data present radiation hardening post proton irradiated sample. However hardning per irradiation damage region is lower than Cu ion irradiation result.
- This result upset the SRIM calculation data which has no irradiation damage near-surface region.
• Analysis of microstructure transition under high energy electron irradiation
- Investigation of high radiation tolerant ability of high entropy alloy, high voltage electron microscopy(HVEM) is performed for in-situ defect mobility analysis at CrFeCoNi high entropy dendrite and Cu solid solution inter-dendrite.
- After electron irradiation, Cu solid solution inter-dendrite has stacking fault tetrahedra and CrFeCoNi high entropy phase has stacking fault.
- Both phase has no micro structure transition at 600 ℃ in TEM, but interface between CrFeCoNi high entropy dendrite and Cu solid solution inter-dendrite splayed. Based on this result, high temperature high voltage electron irradiation condition is determined to 150 ℃.
- After 150 ℃, high voltage electron irradiation, stacking fault tetrahedra in Cu solid solution inter-dendrite disappeared in very short period and stacking fault in CrFeCoNi high entropy dendrite has stability in same condition.
• Application of high entropy alloy as advanced nuclear materials
- Evaluation of application of high entropy alloy for advanced nuclear materials, hardness comparison of heavy ion irradiated conventional alloy and result indicates both data has similar radiation hardening effect.
- Summarizing the research, high entropy alloy has less surface morphology evolution, swallow sub-grain area thickness, defect creation·movement·slow annihilation time, smaller micro hardeness hardening effect and this indicate superb radiation resistibility of high entropy alloy.
(출처: Summary 13p)
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총연구비 (DetailSeriesProject) : | - |
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과제수행기간(LeadAgency) : | - |
연구목표(Goal) : | - |
연구내용(Abstract) : | - |
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