초록 ▼

III. 연구개발의 내용 및 범위
◦ 개발합금 크리프 특성 우수한 원인 규명
◦ 개발합금 상용코팅 적용 후 코팅계면 분석 및 개선안 도출과 검증
◦ 코팅 후 상용대비 크리프 특성 해석
◦ 단결정 개발합금 모델 부품 적용성 평가
◦ 개발 Ti합금의 중간재(bloom) 제조기술 확립
- 균질조성의 고성형성 Ti합금 VAR 잉고트 제조연구
- local texture, microtexture 등을 고려한 잉고트 파쇄공정 설계
- 초정 α상 조직 미세화 단조공정설계(3μm이하 제어) 및 중간재

III. 연구개발의 내용 및 범위
◦ 개발합금 크리프 특성 우수한 원인 규명
◦ 개발합금 상용코팅 적용 후 코팅계면 분석 및 개선안 도출과 검증
◦ 코팅 후 상용대비 크리프 특성 해석
◦ 단결정 개발합금 모델 부품 적용성 평가
◦ 개발 Ti합금의 중간재(bloom) 제조기술 확립
- 균질조성의 고성형성 Ti합금 VAR 잉고트 제조연구
- local texture, microtexture 등을 고려한 잉고트 파쇄공정 설계
- 초정 α상 조직 미세화 단조공정설계(3μm이하 제어) 및 중간재 (bloom)제조
◦ 개발 Ti합금의 열처리설계 및 용접/접합성 평가
- 중간재의 열처리설계 및 특성 개선 연구
- 중간재의 기계적 특성 평가 및 목표치 비교
- 중간재에 대한 TIG 용접성 및 접합 특성평가

Abstract ▼

Two strategic metallic materials for military applications have been investigate to enhance the performance and the efficiency. In order to enhance the efficiency of aero-engines, increasing turbine inlet temperature (TIT) and application high performance alloys for the components are inevitable. Cr

Two strategic metallic materials for military applications have been investigate to enhance the performance and the efficiency. In order to enhance the efficiency of aero-engines, increasing turbine inlet temperature (TIT) and application high performance alloys for the components are inevitable. Creep tests of developed alloys and commercial single crystal alloy were conducted during 1st year of this project. The dislocation structures after creep tests were observed to investigate the deformation mechanism in this year. Anisotropy of SRZ (secondry reaction zone) which formed between bond coat and substrate during heat treatmnet after coating was discussed. New coating procedures were also suggested to prevent the formation of secondary reaction zone and then verified with microstructural observation and creep tests. A model blade which is used in aero engine were cast with the developed alloy to explore the application of the new alloy.
Optimum ingot breakdown process, and high temperature oxidation property and weldability of high strength and high formability Ti alloy were investigated by computational and experimental approaches. Firstly, Ti alloy for indicating lower beta transus temperature and higher elongation at room temperature was re-designed by adding other elements such as Mo, Zr and Sn, and reducing Al element in Ti-6Al-4Fe-0.25Si alloy. Through V bending and tensile test results for candidate Ti alloys, Ti-(4~6)Al-4Fe-Si alloy was chosen as high strength and high formability Ti alloy. In order to achieve the grain refinement of alpha and beta phases, optimum process conditions for first and second ingot breakdown processes was determined by using the recrytallization behavior and multi-step deformation. In first ingot breakdown process, the optimum process condition was obtained by two-step beta forging that leads to dynamic recrysatllization as well as static recrystallization. the optimum condition of second ingot breakdown process was achieved by the multi-step deformation controlling the temperature and strain in dynamic condition.
High temperature oxidation tests of Ti-(4~6)Al-4Fe-Si alloy, meanwhile, were carried out and compared with Ti-6Al-4V alloy. Ti-(4~6)Al-4Fe-Si alloy exhibited superior oxidation resistance better than commercial Ti-6Al-4V. Finally, the weldability of Ti-(4~6)Al-4Fe-Si alloy will be compared with different titanium alloys such as Ti-6Al-4V, Ti-3Al-2.5V and SP-700. The TIG welding technique of titanium alloys was optimized through TIG welding tests with different TIG welding variables.

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 보고서 초록 ... 3
• 요약문 ... 4
• SUMMARY ... 6
• CONTENTS ... 7
• 목차 ... 8
• 제1장 연구개발과제의 개요 ... 9
• 제2장 국내외 기술개발 현황 ... 10
• 제3장 연구개발수행 내용 및 결과 ... 12
• 1절 비행체 엔진소재 개발 ... 12
• 2절 고성형성 Ti합금 판재 및 응용부품 제조기술 개발 ... 19
• 제4장 목표달성도 및 관련분야에의 기여도 ... 29
• 제5장 연구개발결과의 활용계획 ... 30