표제지
목차
Abstract 9
Ⅰ. 서론 11
Ⅱ. 이론적 배경 14
1. 알루미늄 14
2. 탄소 기반 나노물질 16
2.1. 풀러렌 16
2.2. 탄소나노튜브 17
3. 금속 기지 복합재 20
4. Laser Powder Bed Fusion (LPBF) 22
Ⅲ. 실험방법 26
1. Al/C₆₀ 복합재의 제조 공정 조건 26
1.1. 볼 밀링 공정을 활용한 Al/C₆₀ 복합분말 제조 26
1.2. Al/C₆₀ 복합재의 LPBF 공정 조건 30
2. Al/MWCNT 복합재의 제조 공정 조건 36
2.1. 볼 밀링 공정을 활용한 Al/MWCNT 복합분말 제조 36
2.2. Al/MWCNT 복합재의 LPBF 공정 조건 38
3. 분석 및 평가 42
3.1. 미세조직 관찰 및 분석 42
3.2. 기계적 특성 평가 44
Ⅳ. 실험 결과 및 고찰 45
1. LPBF 복합재의 미세조직 분석 45
1.1. 광학현미경 (OM) 및 주사전자현미경 (FE-SEM) 분석 45
1.2. 밀도 측정 및 레이저 반사율 분석 52
1.3. 내부 기공 분석 58
1.4. XRD 분석 63
2. LPBF 복합재의 기계적 특성 평가 72
2.1. 나노경도 분석 72
2.2. 탄성계수 분석 75
Ⅴ. 결론 80
Ⅶ. 참고문헌 84
Table. 3.1. LPBF process conditions for Al/1 vol.% C₆₀ 32
Table. 3.2. Energy densities according to laser conditions of LPBFed Al/1 vol.% C₆₀ composites. 35
Table. 3.3. Energy densities according to laser conditions of LPBFed Al/2 vol.% MWCNT composites. 41
Table. 4.1. Density measurement using the Archimedes method and relative density of the LPBFed Al/1 vol.% C₆₀ composites. 55
Table. 4.2. Density measurement using the Archimedes method and relative density of the LPBFed Al/2 vol.% MWCNT composites. 56
Table. 4.3. Nanohardness (GPa) of the LPBFed Al/1 vol.% C₆₀ composites. 74
Table. 4.4. Nanohardness (GPa) of the LPBFed Al/2 vol.%MWCNT composites. 74
Table. 4.5. Elastic modulus (GPa) of the LPBFed Al/1 vol.% C₆₀ composites. 78
Table. 4.4. Elastic modulus (GPa) of the LPBFed Al/2 vol.%MWCNT composites. 78
Fig. 2.1. Types of carbon nanotubes. 19
Fig. 2.2. Schematic of the LPBF process. 24
Fig. 2.3. Schematic illustration the most influential LPBF process parameters. 25
Fig. 3.1. SEM images of starting powders; (a) pure Al, (b) C₆₀. 28
Fig. 3.2. SEM images of ball-milled Al/1 vol.% C₆₀ composite powders for different milling time; (a) 22 h milled, (b) 24 h milled, (c) 26 h milled, and (d) 28 h milled. 29
Fig. 3.3. Schematic of the hexagonal grid laser scanning tracks on each powder layer. 33
Fig. 3.4. 25 cuboidal LPBFed Al/1 vol.% C₆₀ composites. 34
Fig. 3.5. SEM images of starting powders; (a) MWCNT, and ball-milled Al/2 vol.% MWCNT composite powders for different milling time; (b) 18 h milled, (b) 20 h... 37
Fig. 3.6. 25 cuboidal LPBFed Al/2 vol.% MWCNT composites. 40
Fig. 4.1. (a), (c) OM images and (b), (d) SEM images of the LPBFed composites with the various condition of laser power and scan speed. (a)-(b) LPBFed Al/1 vol.%... 51
Fig. 4.2. Laser reflectivity of Al/1 vol.% C₆₀ and Al/2 vol.% MWCNT composite powders. 57
Fig. 4.3. X-ray micro-computed tomography (μ-CT) images of the LPBFed Al/1 vol.% C₆₀ composites with the same (a) group L1, and (b) group L4 (blue color is pore). 60
Fig. 4.4. Pore size distribution of the LPBFed Al/1 vol.% C₆₀ composites obtained from μ-CT analysis data in each group; (a) L1, (b) L2, (c) L3, and (d) L4. 62
Fig. 4.5. The XRD patterns of (a) the powders; C₆₀, Al, and ball-milled Al/1 vol.% C₆₀ composite powders, and (b)-(e) the LPBFed Al/1 vol.% C₆₀ composites in each... 68
Fig. 4.6. The XRD patterns of (a) the powders; MWCNT, Al, and ball-milled Al/2 vol.% MWCNT composite powders, and the LPBFed Al/2 vol.% MWCNT... 70
Fig. 4.7. (a) A comparison between the FWHM of the peaks of Al powders, ball milled Al/1 vol.% C₆₀ composite powders, and LPBFed Al/1 vol.% C₆₀ composites.... 71
Fig. 4.8. Comparison of nanohardness and elastic modulus of LPBFed Al/1 vol.% C₆₀, and Al/2 vol.% MWCNT composites in the same laser power group. 79