표제지
목차
국문요약 5
Abstract 6
감사의 글 7
제 1 장. 서론 8
제 2 장. 합금의 종류 및 거동특성 10
2.1. 알루미늄과 그 합금 10
① 1000계 알루미늄 11
② 2000계 합금 (Al-Cu, Al-Cu-Mg계 합금) 11
③ 3000계 합금 (Al-Mn계 합금) 12
④ 4000계 합금 (Al-Si, Al-Si-Cu-Mg계 합금) 12
⑤ 5000계 합금 (Al-Mg계 합금) 12
⑥ 6000계 합금 (Al-Mg-Si계 합금) 13
⑦ 7000계 합금 (Al-Zn-Mg, Al-Zn-Mg-Cu계 합금) 14
⑧ 기타 합금 14
2.2. 마그네슘과 그 합금 15
① 마그네슘 합금 주물 16
② 마그네슘 전신재 18
③ 마그네슘 합금의 변형기구와 성형성 20
2.3. 가공ㆍ재결정 22
① 미끄러짐 변형 22
② 쌍정변형(Twinning) 23
제 3 장. 압출 종류 및 압출 이론 26
3.1. 압출공정 (壓出 : Extrusion) 26
3.2. 압출압력과 재료유동에 미치는 제인자 30
3.3. 중공재, 형재, 복합재의 압출 38
3.4. 특수한 압출 가공 43
3.4.1 정수압압출 43
3.4.2 연속압출 44
3.4.3 반용융 압출 44
3.4.4 충격 압출 48
3.4.5 측압 부가 압출 49
3.5. 압출 중에 일어나는 하중과 응력계산 50
3.5.1 요소분석 50
3.5.2 Eisbein과 Sachs 의 이론 52
3.5.3 Geleji 이론 56
제 4 장. 유한요소 해석 61
4.1. 이론적 배경 63
4.2. 유한요소해석 및 고찰 65
4.3. 유한요소해석에 따른 금속조직학적 관찰 75
제 5 장. 결론 80
제 6 장. 참고문헌 82
Table 1 Variety and usage of the extrudate 26
Table 2 Hot extrusion conditions of the materials 27
Table 3 Variety defect and origination cause for the hot extrusion 34
Table 4 Process parameter used in the 3D FE-Simulation 67
Table 5 Process parameter used in the 3D FE-Simulation 67
Table 6 composition of the etchant 76
Fig 1 Schematic drawing of the various extrusion process 28
Fig 2 Extrusion load curve regarding to the time and the variety extrusion 31
Fig 3 Metal flow at the near die exit 32
Fig 4 Metal flow in the hot direct extrusion with copper 33
Fig 5 The shape and the friction stress at the near dies bearing 35
Fig 6 Effect of the bearing plane shape regarding to surface intensity of the illumination with aluminum alloy extrudate 36
Fig 7 Temperature-Friction coefficient curve regarding to a lubricant 36
Fig 8 Dies type for the extrusion 38
Fig 9 Mandrel type for tude extrusion 39
Fig 10 Operating sequence of the press for tube extrusion 39
Fig 11 Various type of the extrusion for composite materials 40
Fig 12 Work process of the Nb-Ti super-conductivity line for copper stabilization 42
Fig 13 Schematic drawing of the hydrostatic pressure extrusion 43
Fig 14 Schematic drawing of the semi-solid extrusion 45
Fig 15 Process of the fabrication and the deformation for semi-solid materials 47
Fig 16 Various type of the impact extrusion 48
Fig 17 Stress states of extrusion without friction 52
Fig 18 The states of stress within dies and container, considering friction between container and billet 54
Fig 19 Schematic illustration of forward extrusion forces 57
Fig 20 Metal flow in container 57
Fig 21 The compression of dead metal zone 58
Fig 22 Schematic drawing of extrusion process 65
Fig 23 Assembly of the meshed billet, die, ram and container 66
Fig 24 Mesh generation profile for the extrusion 67
Fig 25 3-dimensional Material flow of the final step #307 68
Fig 26 2D Material flow of the final step #307(XZ Plane) 69
Fig 27 2D Material flow of the final step #307(YZ plane) 69
Fig 28 2D Enlarged material flow in the final step #307(YZ plane) 70
Fig 29 3D Velocity vector profile in the final step #307(YZ plane) 71
Fig 30 Stroke-Load Curve for ram travel (total 3mm) 72
Fig 31 Distribution of the maximum principle stress after extrusion 73
Fig 32 Distribution of the effective strain after extrusion 73
Fig 33 Strain distribution of the final step #307 75
Fig 34 Optical Microscopy of as cast (X100) 77
Fig 35 Optical Microscopy of a longitudinal center view for the extruded sheet (X200) 77
Fig 36 Optical Microscopy of a longitudinal edge view for the extruded sheet (X200) 77
Fig 37 Variation of average grain size as materials 78
Fig 38 Comparison of mechanical properties regarding to materials 79