In-situ 공정에 의한 Titanium 기지 복합재료의 제조 및 기계적 특성 평가 = Fabrication and Mechanical Property of Titanium Matrix composites by In-situ Process

다국어 초록 (Multilingual Abstract)

High temperature titanium alloys have been used as structural materials for aero-space applications because of their low density, high strength, corrosion resistance and so on. However titanium alloys in aero-space industry is strictly limited by the working temperature, most of the titanium alloys can only work at the temperature up to 873K. For higher working temperature, titanium matrix composites (TMCs) which are improved mechanical properties by ceramic reinforcements are applied.
To manufacture TMCs, there are two ways classified by how to insert reinforcements into titanium matrix. One is ex-situ process which is inserted reinforcements as it is and the other is in-situ process that reinforcements were synthesized in titanium matrix by chemical reaction with the adding elements. Until now, several manufacturing processes, based on ex-situ and in-situ, have been developed, However, there are some limitations such as interfacial reaction between matrix and reinforcements, agglomeration of reinforcements and additional pre-treatment.
Therefore, in this study, the main purpose is an in-situ synthesis of sound (TiB+TiC) hybrid TMCs by vacuum induction melting method which makes sound titanium melts without oxidation and economical efficiency. Among the reinforcements for TMCs, TiB and TiC are considered to be suitable because of their high modulus, high thermal stability and similar thermal expansion coefficient to titanium.
The melting route was adopted to synthesize the commercial pure titanium (cp Ti) and boron carbide (B4C) with volume fractions of reinforcements (5, 10, 20%) and B4C particle size (1~3 mm, 150 ㎛). The reinforcements were synthesized by adding B4C into cp Ti. After the in-situ synthesis of TMCs, XRD and EPMA elemental mapping were carried out to confirm the distribution and shapes of reinforcements. To verify mechanical properties of TMCs, Brinell hardness test and tensile test at room temperature were carried out.

목차 (Table of Contents)

• 1. 서론 1
• 2. 이론적 배경 4
• 2.1 타이타늄 기지 복합재료의 특성 4
• 2.2 타이타늄 기지 복합재료의 제조방법 5
• 2.3 타이타늄 기지 복합재료의 강화상 6
• 2.4 타이타늄 기지 복합재료의 연구 현황 9
• 3. 실험 방법 15
• 3.1 정밀주조용 주형 제작 15
• 3.2 타이타늄 기지 복합재료의 반응생성 합성 및 정밀주조 18
• 4. 실험 결과 및 고찰 23
• 4.1 타이타늄 기지 복합재료의 미세조직 23
• 4.2 타이타늄 기지 복합재료의 상분석 25
• 4.3 열역학적 고찰 36
• 4.4 타이타늄 기지 복합재료의 기계적 특성 평가 37
• 5. 결론 43
• 6. 참고문헌 44
• ABSTRACT 46