표제지
목차
국문 요약 14
Abstract 16
1. 서론 18
2. 이론적 배경 21
2.1. 타이타늄 21
2.2. 스테인리스강 23
2.3. Ti/STS 접합방법 25
2.3.1. 마찰교반용접(Friction Stir welding) 25
2.3.2. 폭발용접 25
2.3.3. 천이액상확산접합 (Transient liquid phase bonding, TLP bonding) 26
2.4. 브레이징 28
2.4.1. 브레이징의 정의 28
2.4.2. 브레이징의 원리 29
2.4.3. 브레이징의 특징 29
2.5. Ti/STS 브레이징 30
2.6. 비정질 금속 (금속유리, Metallic Glass) 31
2.7. 전해부식 36
3. 실험 방법 36
3.1. 모재의 조성 및 시편크기 36
3.2. 삽입금속과 확산 방지층의 설계 37
3.3. 삽입금속의 특성 분석 40
3.4. 접합 공정 41
3.5. 미세조직 분석 42
3.5.1. 미세조직 및 상분석 42
3.6. 기계적 특성 분석 43
3.6.1. 전단강도 평가 43
3.7. 부식특성 분석 44
3.7.1. 전해부식시험 44
4. 실험 결과 및 고찰 46
4.1. 비정질 삽입 금속 46
4.1.1. X선 회절패턴 분석 및 열분석 46
4.2. Ti/STS 브레이징 47
4.2.1. 미세조직 분석 47
4.2.2. 강도평가 54
4.2.3. 파단면 & XRD 분석 56
4.3. Ti/STS 브레이징 - Ni interlayer 58
4.3.1. 미세조직 분석 58
4.3.2. 강도평가 65
4.3.3. 파단면 & XRD 분석 67
4.4. Ti/STS 브레이징 - Ni+Cr interlayer 72
4.4.1. 미세조직 분석 73
4.4.2. 강도평가 76
4.4.3. 파단면 & XRD 분석 77
4.5. 내식성 평가 79
4.4.1. 미세조직 79
4.4.2. 강도평가 83
5. 결론 85
6. 참고문헌 88
Table. 2.1. Various brazing filler metals used in Ti/STS dissimilar bonding. 31
Table. 3.1. Chemical compositions of base materials 37
Table. 4.1. EDS chemical analysis of marked points in Fig. 4.2 49
Table. 4.2. EDS chemical analysis of marked points in Fig. 4.4 52
Table. 4.3. EDS chemical analysis of marked points in Fig. 4.5 53
Table. 4.4. EDS chemical analysis of marked points in Fig. 4.13 63
Table. 4.5. EDS chemical analysis of marked points in Fig. 4.14 64
Table. 4.6. EDS chemical analysis of marked points in Fig. 4.16 68
Table. 4.7. Thermal expansion coefficient of materials. 72
Fig. 2.1. Schematic illustration of beta... 22
Fig. 2.2. Influence of alloying elements on phase diagrams of Ti alloys 22
Fig. 2.3. Various types of stainless steels 24
Fig. 2.4. Mechanical and physical properties of base materials 24
Fig. 2.5. Schematic illustration of friction stir welding 25
Fig. 2.6. Schematic illustration of explosion welding. 26
Fig. 2.7. Sequential stages assumed in standard models of the TLP process... 27
Fig. 2.8. Schematic illustration of brazing process 28
Fig. 2.9. Wetting state of the liquid at equilibrium 29
Fig. 2.10. Schematic illustration of liquid/solid interface : a)facet,... 33
Fig. 2.11. The effect of composition on glass formation in a regular eutectic... 34
Fig. 2.12. The effect of composition on glass formation in a irregular eutectic... 35
Fig. 3.1. Schematic diagram of the liquidus projection in... 38
Fig. 3.2. Binary phase diagrams: a)Fe-Ti, b)Fe-Ni, c)Fe-Cr and... 39
Fig. 3.3. The solubility properties of Ti and Fe with other elements. 40
Fig. 3.4. Schematic illustration of brazing process and specimen 41
Fig. 3.5. Thermal cycle of brazing process 42
Fig. 3.6. Schematic illustration of the shear strength test 43
Fig. 3.7. Schematic illustration of the electrolytic... 44
Fig. 3.8. Simplified galvanic series in sea water 45
Fig. 4.1. DTA trace of the Zr61Ti17Ni22 filler metal alloy[이미지참조] 46
Fig. 4.2. Microstructure of Ti/STS joint brazed for 15min at a)840℃,... 49
Fig. 4.3. Microstructure of Ti/STS joint brazed at 880℃ for a)10min,... 51
Fig. 4.4. EDS line scanning results of microstructure brazed at 880℃ for 20min. 52
Fig. 4.5. EDS line scanning results of microstructure brazed at 880℃ for 30min. 53
Fig. 4.6. Shear strength of dissimilar joints brazed at various... 55
Fig. 4.7. Shear strength of dissimilar joints brazed at 880℃ at... 55
Fig. 4.8. XRD results of the fracture surfaces of the joints brazed for 15min. 57
Fig. 4.9. XRD results of the fracture surfaces of the joints brazed at 880℃ 57
Fig. 4.10. Microstructure of Ti/STS joint brazed at 880℃ with Ni interlayer... 60
Fig. 4.11. Microstructure of Ti/STS joint brazed at 880℃ with Ni interlayer... 61
Fig. 4.12. Microstructure of Ti/STS joint brazed at 880℃ with Ni interlayer... 62
Fig. 4.13. EDS line scanning results of microstructure brazed at 880℃ with... 63
Fig. 4.14. EDS line scanning results of microstructure brazed at 880℃ with... 64
Fig. 4.15. Variation of bonding strength according to time duration and... 66
Fig. 4.16. Fracture morphology of the brazed joints with Ni interlayer... 68
Fig. 4.17. Fracture morphology of the brazed joints with Ni interlayer... 69
Fig. 4.18. Fracture morphology of the brazed joints with Ni interlayer... 70
Fig. 4.19. XRD results of the fracture surfaces of the joints brazed at 880℃... 71
Fig. 4.20. Microstructure of Ti/STS joint brazed at 880℃ with Ni+Cr... 74
Fig. 4.21. EDS line scanning results of microstructure brazed at 880℃ with... 75
Fig. 4.22. Variation of bonding strength according to time duration and... 76
Fig. 4.23. Fracture morphology of the brazed joints with Ni+Cr interlayer at... 77
Fig. 4.24. XRD results of the fracture surfaces of the joints brazed... 78
Fig. 4.25. Optical microstructures of brazed joint a)before corrosion test, after... 80
Fig. 4.26. Optical microstructures of brazed joint a)before corrosion test, after... 81
Fig. 4.27. Optical microstructures of brazed joint a)before corrosion test, after... 82
Fig. 4.28. Variation of bonding strength according to the corrosion time. 84