臺灣博碩士論文加值系統

摘 要

Al-Cu系合金為高強度熱處理型鋁合金，由於具有低密度、高比強度之特性，是一種理想的航太結構材料。摩擦攪拌銲接(friction stir welding, FSW)是一種新式固態接合銲接法，可避免鋁合金材料在熔融銲接法(fusion welding)中所產生的偏析、熱裂、氣孔及噴濺等現象，而造成機械性質劣化的缺點。本研究選用Al-Cu系2091-T3合金和2024-T651合金作為實驗材料，進行個別單一合金及2091-T3與2024-T651異質鋁合金的FSW接合，經由銲後、自然時效30天和人工時效170°C-8hr等三種時效處理條件，透過微觀組織觀察、硬度試驗、拉伸試驗和SEM分析，來了解微觀組織變化及機械性質間的關係。
在銲道區域可明顯觀察到FSW接合後所呈現出的三個區域。攪拌區(SZ)的特徵是呈現出等軸細微的晶粒結構，熱機影響區(TMAZ) 顯示出晶粒變形和成長，熱影響區(HAZ)的晶粒組織與母材相似。2091-T3合金經FSW接合後，以人工時效所得的接合強度最高。2024-T651合金經FSW接合後，以自然時效所得的接合強度最佳，然仍低於母材強度。2091-T3與2024-T651異質鋁合金在攪拌桿順、逆時針兩個方向迴轉下，經FSW接合並施行時效處理後，以逆時針方向迴轉所得的接合強度較高。

Abstract
Among all heat treatment type aluminum alloys, Al-Cu series alloys have been recognized by its high strength, low density and high specific modulus properties. This significant advantage makes it the perfect structural material for aerospace applications. Friction stir welding (FSW) is a unique solid-state joining process that can prevent material from mechanical properties degradation which is caused by segregate, hot cracking, porosity and spatter in fusion welding during the process.
The 2091-T3 and 2024-T651 were selected from Al-Cu series alloys for this study. Individual alloy FSW joint processes were performed for 2091-T3 and 2024-T651 and bi-alloy FSWs for 2091-T3/2024-T651 were made before other steps. After the welding, The aging treatment of the specimens were performed under the condition of naturally (open-air) aged for 30 days and artificially aged under 170°C for 8 hours. After these three types of aging treatment, the microstructures changes and reactions among mechanical properties were examined through the microstructures observations, hardness testing, and tensile test as well as SEM analysis.
The welding path obviously exhibited three microstructural sections through FSW joint. The stir zone (SZ) characteristically exhibited a refined equiaxed grain structure, the thermomechanically affected zone (TMAZ) demonstrated macroscopic deformation and grain growth, beyond the TMAZ a heat affected zone (HAZ) where changes were similar to parent metal (PM) with grain organization. 2091-T3 alloy has the highest joint strength of the artificial aging after FSW joint. 2024-T651 alloy showed highest joint strength of the natural aging after FSW joint, but it still lower than the strength of parent metal. The bi-alloys 2091-T3/2024-T651 presented a great joint strength with counterclockwise rotation after FSW joint, investigated by aging treatments with the cylindrical tool in both clockwise and counterclockwise directions.

目 錄

中文摘要……………………………………………………………. Ⅰ
英文摘要……………………………………………………………. Ⅱ
目錄…………………………………………………………………. Ⅳ
表目錄………………………………………………………………. Ⅶ
圖目錄………………………………………………………………. Ⅷ

第一章 前言……………………………………………………… 1
第二章 文獻探討………………………………………………… 4
2-1 鋁合金材料…………………………………………………… 4
2-1-1 鍛造用鋁及鋁合金之編號………………………………… 5
2-1-2 鋁及鋁合金之質別記號…………………………………… 5
2-2 2xxx 系列合金的特性………………………………………… 6
2-2-1 2024合金…………………………………………………… 6
2-2-2 2091合金…………………………………………………… 6
2-3 鋁合金之析出硬化…………………………………………… 7
2-3-1 Al-Cu合金析出硬化的基本過程………………………… 7
2-3-2 析出硬化熱處理之步驟…………………………………… 8
2-3-3 2024與2091合金之析出行為……………………………… 9
2-4 鋁合金之銲接性……………………………………………… 10
2-5 摩擦攪拌銲接原理…………………………………………… 11
2-6 摩擦攪拌銲接之製程………………………………………… 12
2-7 摩擦攪拌銲接銲道區之金相觀察…………………………… 13
2-8 Al-Li 合金之摩擦攪拌銲接………………………………… 13
第三章 實驗方法及步驟……………………………………………24
3-1　材料備製……………………………………………………… 24
3-2 銲接設備…………………………………………………………24
3-3 攪拌桿設計………………………………………………………24
3-4 銲接條件…………………………………………………………25
3-5 銲接程序…………………………………………………………25
3-6 時效處理…………………………………………………………26
3-7 微觀組織觀察及機械性質測試…………………………………26
3-7-1 微觀組織觀察……………………………………………… 26
3-7-2 微硬度試驗…………………………………………………. 27
3-7-3 拉伸試驗……………………………………………………. 27
第四章 實驗結果與討論……………………………………………34
4-1 2091鋁合金之FSW接合性質….……………………………… 34
4-1-1 可銲接範圍…………………………………………………. 34
4-1-2 微觀組織觀察………………………………………………. 34
4-1-3 微硬度試驗…………………………………………………. 35
4-1-4 拉伸試驗……………………………………………………. 36
4-2 2024鋁合金之FSW接合性質…………………………………. 38
4-2-1 可銲接範圍....……………………………………………….38
4-2-2 微觀組織觀察………………………………………………. 38
4-2-3 微硬度試驗…………………………………………………. 39
4-2-4 拉伸試驗……………………………………………………. 40
4-3 2091與2024異質鋁合金FSW接合性質....…………….…….. 42
4-3-1 攪拌桿順時針方向迴轉……………………………………. 42
4-3-1-1 外觀檢查……………………………………………….. 42
4-3-1-2 微觀組織觀察…………………………………….……. 42
4-3-1-3 微硬度試驗…………………………………….………. 43
4-3-1-4 拉伸試驗……………………………………….………. 44
4-3-2 攪拌桿逆時針方向迴轉……………………………………. 45
4-3-2-1 外觀檢查………….……………………………………. 45
4-3-2-2 微觀組織觀察………………………………….………. 45
4-3-2-3 微硬度試驗……………………………………….……. 45
4-3-2-4 拉伸試驗………………………………………….……. 47
第五章 結論………………………………………………………….89
參考文獻……………………………………………………………… 91

表目錄

表2-1 鍛造用鋁及鋁合金之編號系統……………………………….15
表2-2 鋁及鋁合金的質別記號……………………………………….16
表3-1 2091與2024合金化學成分組成(wt%)………………………..28
表3-2 試片FSWs接合後進行之各種時效處理條件………………...29
表4-1 2091-T3 FSWs拉伸試驗結果………………………………….49
表4-2 2024-T651 FSWs拉伸試驗結果……………………………...49
表4-3 2091/2024異質鋁合金FSWs攪拌桿順時針迴轉拉伸試驗結果50
表4-4 2091/2024異質鋁合金FSWs攪拌桿逆時針迴轉拉伸試驗結果50

圖目錄

圖2-1 Al-Cu合金平衡相圖…………………………………………..17
圖2-2 Al-4％Cu合金析出序列……………………………………...18
圖2-3 時效時間對Al-4％Cu合金之強度或硬度的影響.....………19
圖2-4 時效溫度與時間對Al-4％Cu合金之降伏強度的影響……...20
圖2-5 Al-Cu合金析出硬化熱處理過程.....……………………… 21
圖2-6 摩擦攪拌銲接製程之示意圖………………………………….22
圖2-7 銲道推進邊與退出邊示意圖………………………………….22
圖2-8 FSW 銲道橫截面顯微結構示意圖…..……………………….23
圖3-1 實驗流程……………..………………………..…………… 30
圖3-2 攪拌桿示意圖………………………………………………….31
圖3-3 摩擦攪拌桿幾何形狀設計……………..……………..…….31
圖3-4 摩擦攪拌桿沿接合線移動前進情形………………………….32
圖3-5　拉伸試片規格……………………………..………………… 32
圖3-6 拉伸試片取樣位置示意圖……..……………………….....33
圖4-1 2091-T3 FSW可銲接範圍.……….……............... 51
圖4-2 2091-T3 FSW，在各種製程參數下的接合外觀:(a)2500rpm、
187mm/min；(b) 1100rpm、87mm/min；(c)800rpm、 87mm/min；(d) 320rpm、127mm/min………………………………… 52
圖4-3 2091-T3 FSW橫截面巨觀圖………………………………… 53
圖4-4 2091-T3 母材微觀組織圖，×200…………………………….53
圖4-5 2091-T3 FSW銲道SZ微觀組織圖，×200…………………… 54
圖4-6 2091-T3 FSW推進邊SZ/TMAZ微觀組織圖，×200…………… 54
圖4-7 2091-T3 FSW退出邊SZ/TMAZ微觀組織圖，×200…….….. 55
圖4-8 2091-T3 FSW推進邊HAZ微觀組織圖，×200……………… 55
圖4-9 2091-T3 FSW退出邊HAZ微觀組織圖，×200………….... 56
圖4-10 2091-T3 FSW銲後和自然時效橫截面微硬度分佈圖......56
圖4-11 2091-T3 FSW自然時效和人工時效橫截面微硬度分佈圖...57
圖4-12 2091-T3 FSW各區位置橫截面微硬度分佈圖............ 57
圖4-13 2091-T3拉伸試驗斷裂情形：(a)自然時效試片AN1，(b)自
然時效試片AN2；(c)人工時效試片AH1，(d)人工時效試
片AH2………………………………………………………………… 58
圖4-14 2091-T3母材拉伸試驗斷裂情形..…………….……………59
圖4-15 2091-T3人工時效試片AH2斷裂情形：(a)橫截面斷裂位
置巨觀圖；(b)斷裂位置微觀組織圖，×50；(c)斷裂位置
微觀組織圖，×50……………………………….………………………59
圖4-16 2091-T3 FSW拉伸強度比較………..……………….………60
圖4-17 2024-T651 FSW可銲接範圍………..……………….………61
圖4-18 2091-T651 FSW，在各種製程參數下的接合外觀:(a)1600
rpm、127mm/min；(b) 800rpm、87mm/min；(c) 550rpm、
87mm/min；(d) 1600rpm、87mm/min…………..…………………… 62
圖4-19 2024-T651 FSW橫截面巨觀圖.……………….…………….63
圖4-20 2024-T651母材微觀組織圖，×200..…………….…..……63
圖4-21 2024-T651 FSW銲道SZ微觀組織圖，×200….…………… 64
圖4-22 2024-T651 FSW推進邊SZ/TMAZ微觀組織圖，×200……. 64
圖4-23 2024-T651 FSW退出邊SZ/TMAZ微觀組織圖，×200……. 65
圖4-24 2024-T651 FSW推進邊HAZ微觀組織圖，×200………….. 65
圖4-25 2024-T651 FSW退出邊HAZ微觀組織圖，×200………….. 66
圖4-26 2024-T651 FSW銲後和自然時效橫截面微硬度分佈圖….…66
圖4-27 2024-T651 FSW三種人工時效條件橫截面微硬度分佈圖.. 67
圖4-28 2024-T651 FSW自然時效和人工時效橫截面微硬度分佈圖.67
圖4-29 2024-T651 FSW各區位置橫截面微硬度分佈圖....……...68
圖4-30 2024-T651拉伸試驗斷裂情形：(a)自然時效試片BN1，(b)
自然時效試片BN2；(c)人工時效試片BH1，(d)人工時效試
片BH2………....…………………………………….………... 69
圖4-31 2024-T651拉伸試驗斷裂情形：(a)自然時效試片BN2橫截
面斷口；(b)在SEM下，破斷口微觀組織，×400；(c)在SEM
下，酒渦型微觀破損型態，×4000……..……………………. 70
圖4-32 2024-T651自然時效試片BN1橫截面斷裂位置巨觀圖與微
觀組織圖……………………………………………………..... 71
圖4-33 2024-T651 FSW拉伸強度比較…………..………………….71
圖4-34 2091-T3與2024-T651異質鋁合金FSW攪拌桿順時針方向
迴轉對接接合示意………………………………………........ 72
圖4-35 2091-T3與2024-T651異質鋁合金FSW攪拌桿順時針方向
迴轉接合外觀.…...........................................72
圖4-36 2091-T3與2024-T651雙合金FSW，攪拌桿順時針方向迴
轉橫截面巨觀和微觀組織圖：(a)橫截面巨觀圖；(b)2091
SZ微觀組織圖，×200；(c)雙合金交界SZ微觀組織圖，
×50；(d)雙合金交界SZ微觀組織圖，×50；(e) 2024 SZ微
觀組織圖，×200………………………………………............ 73
圖4-37 2091-T3與2024-T651異質鋁合金FSW推進邊SZ/TMAZ微
觀組織圖，×200 ......................................... 74
圖4-38 2091-T3與2024-T651異質鋁合金FSW推進邊HAZ微觀組
織圖，×200.............................................. 74
圖4-39 2091-T3與2024-T651異質鋁合金FSW退出邊SZ/TMAZ微
觀組織圖，×200 ......................................... 75
圖4-40 2091-T3與2024-T651異質鋁合金FSW退出邊HAZ微觀組
織圖，×200............................................... 75
圖4-41 2091-T3與2024-T651異質鋁合金FSW攪拌桿順時針方
向迴轉自然時效和人工時效橫截面微硬度分佈圖...........…. 76
圖4-42 2091-T3與2024-T651異質鋁合金拉伸試驗斷裂情形：(a)
自然時效試片CN1；(b)自然時效試片CN2；(c)自然時效試
片CN橫截面斷口…..………………........…………………… 77
圖4-43 2091-T3與2024-T651異質鋁合金FSW拉伸試驗斷裂情
形：(a)人工時效試片CH1；(b)人工時效試片CH2橫截面
巨觀圖；(c)人工時效試片CH2橫截面微觀組織圖....…...… 78
圖4-44 2091-T3與2024-T651異質合金FSW試片CH2拉伸試驗
SEM微觀組織觀察：(a)破斷口呈45°方向破壞，×30；(b)
破斷口微觀組織，×100；(c)破斷口微觀組織，×200；(d)酒
渦型微觀破損型態，×2000…..…………..…………....…...… 79
圖4-45 2091-T3與2024-T651異質鋁合金FSW攪拌桿順時針
方向迴轉自然時效和人工時效拉伸強度比較................... 80
圖4-46 2091-T3與2024-T651異質鋁合金FSW攪拌桿逆時針
方向迴轉對接接合示意圖…………………..................... 81
圖4-47 2091-T3與2024-T651異質鋁合金FSW攪拌桿逆時針方向
迴轉接合外觀....……......................................81
圖4-48 2091-T3與2024-T651異質鋁合金FSW，攪拌桿逆時針
方向迴轉橫截面巨觀和微觀組織圖：(a)橫截面巨觀圖；
(b)2091 SZ微觀組織圖，×200；(c)雙合金交界SZ微觀組
織圖，×50；(d)雙合金交界SZ微觀組織圖，×50；(e) 2024
SZ微觀組織圖，×200…..……...….…..…………………… 82
圖4-49 2091-T3與2024-T651異質鋁合金FSW推進邊SZ/TMAZ
微觀組織圖，×200........................................ 83
圖4-50 2091-T3與2024-T651異質鋁合金FSW推進邊HAZ微觀
組織圖，×200……......................................... 83
圖4-51 2091-T3與2024-T651異質鋁合金FSW退出邊SZ/TMAZ微
觀組織圖，×200….........................................84
圖4-52 2091-T3與2024-T651異質鋁合金FSW 退出邊HAZ微觀組
織圖，×200………......................................... 84
圖4-53 2091-T3與2024-T651異質鋁合金FSW 攪拌桿逆時針方向
迴轉自然時效和人工時效橫截面微硬度分佈圖..................85
圖4-54 2091-T3與2024-T651異質鋁合金FSW 拉伸試驗斷裂情形：
(a)自然時效試片DN1；(b)自然時效試片DN2；(c)人工時效
試片DH1；(d)人工時效試片DH2………...…………………. 86
圖4-55 2091-T3與2024-T651異質鋁合金FSW 拉伸試驗斷裂情形：
(a)自然時效試片DN1橫截面巨觀圖；(b)自然時效DN1橫
截面微觀組織圖，×50..………….......................………87
圖4-56 2091-T3與2024-T651異質鋁合金FSW 攪拌桿逆時針方向
迴轉自然時效和人工時效拉伸強度比較………………......... 88

參考文獻

1. N. J. Woodward and A.Thomas, "Variable polarity plasma arc welding of mm aluminum alloys", Science Technology Welding Joining, 5(1), 2000, pp.21-25.
2. N. J. Woodward, et al. "Process enhancement for automated GTA and plasma welding of aluminum alloys", 7th International Conference：Joint in Aluminium：INALCO 98, Cambridge (UK), 1998.
3. P. E. Irving and G. Bussu, "The role of residual stress and heat affected zone properties on fatigue crack propagation in friction stir welded 2024-T351 aluminium joints", Internation Journal of Fatigue, Vol. 25, 2003, pp.77-88.
4. 張志溢、黃志青，"摩擦旋轉攪拌製程之新近發展與應用"，科儀新知，第25卷第5期，(2004) pp.59-73.
5. W. M. Thomas, E. D. Nicholas, J.C. Needham, M.G. Murch, P. TempleSmith, and C. J. Dawes, The Welding Institute, TWI, International Patent Application No. PCT/GB92/02203 and GB Patent Application No.9125978.8, 1991.
6. W. M. Thomas, E. D. Nicholas, J. C. Needham, M. G. Murch, P. TempleSmith, and C. J. Dswes, The Welding Institute, TWI, U.S. Patent No.5, 460, 317, 1995.
7. W. M. Thomas, "Friction stir welding and related friction process characteristics", 7th International Conference：Joints in Aluminium： INALCO 98, Cambridge (UK), 1998.
8. C. J. Dawes and W. M. Thomas, "Friction stir process welds aluminium alloys", The Welding Journal, 75(3), 1996, pp.41-46.
9. C. J. Dawes, E. J. R. Spring, and D. G. Staines, "Friction stir welding aluminium alloys 5083 - increased welding speed", TWI Report, Aug. 1999.
10. P. L. Threadgill, "Friction stir welding – the state of the art", TWI Report, May 1999.
11. W. Thomas and K. Johnson, "Friction stir wins millennium products recognition", TWI, November 1998, pp.1-2.
12. R. Fenn and W. M. Thomas, "The friction stir welding process", LIGHT METAL AGE, October 2001.
13. E. P. Patrick and M. L. Sharp, "Joining aluminum auto body structure", SAE Paper 920282, 1992.
14. R. S. Jame, Aluminum-Lithium Alloys, ASM Metals Handbook, 10th Ed., Vol. 2, 1990, pp.178-184.
15. Donald R. Askeland著、陳皇鈞譯，材料科學與工程，台北：曉園出版社，(1989) pp.365-374.
16. 機械月刊編輯，金屬符號，台北：機械月刊社，(1996) pp.32-42.
17. 黃振賢，機械材料，台北：文京圖書公司，(1990) pp.311-327.
18. R.S. James, "Aluminum-Lithium Alloys", Aluminum Company of America, p.185.
19. 楊智超，鋁及鋁合金熱處理，工業教育研究所，(1991) pp.1-45.
20. K. Xia, "Engineering Materials", pp.436-220, from
http://www.mame.mu.oz.au/materials/200mats2005/7-Phase%20Transformation%205.pdf#search='ALCU%20age%20hardening'
21. 曹啟彰，"表面淨度對7075鋁合金熱處理後之機械性質影響"，大葉大學機械工程研究所碩士論文，(2004) pp.26-29.
22. C. H. Gr and I. Yildiz, "Determining the impact toughness of age-hardened 2024 al-alloy by nondestructive measurements", from http://www.ndt.net/article/wcndt2004/pdf/materials_characterization/139_gur.pdf
23. K. H. Hou and W. A Baeslack Ⅲ, "Characterization of the heat-affected zone in gas tungsten aec welded aluminum 2195-T8", Journal of material Science Letters 15 (1996), pp.239-244.
24. R. P. Martukanitz and P. R. Huwell, "Relationships Involving Process, Microstructure, and Properties of Weldments of Al-Cu and Al-Cu-Li Alloys", Trends in Welding Research, Proceedings of the 4th International Conference, 1995, pp.553-562.
25. P. J. Ditzel and J. C. Lippold, "Microstructure/property relationships in alumimum friction stir welds", Materials Jioning Technology, EWI Report, Aug. 1999, p.17.
26. J. H. Dudas and F. R. Collins, "Preventing weld cracks in high-strength aluminum alloys", Welding Joural, 45(6), 1966, pp.241-249.
27. N. F. Gittos and M. H. Scott, "Heat-Affected Zone cracking of Al-Si-Mg alloys", Welding Journal, 60(6), 1981, pp.95-103.
28. 黃仁佑，"鋁合金銲接熱影響區之特性研究"，國立交通大學機械工程研究所博士論文，(1998) pp.1-7.
29. A. P. Reynold, W. D. Lockwood, and T. U. Seidel, Material Science Forum, 1719, 2000, pp.331-337.
30. M. Guerra, C. Schmidt, J. C. McClure, L. E. Murr, and A.C. Nunes, Material Characteriaztion, 49, 2003, p.95.
31. A. P. Reynold, Science Technology Weld, 5(2), 2000, p.104.
32. A. J. Leonard, "Structure and corrosion resistance of friction stir welds in aluminium alloys 2014A and 7075", TWI Report, Aug. 1999.
33. K. N. Krishnan, Material Science Engineer, A327, 2002, p.246.
34. W. B. Lee, Y. M. Yeon, and S. B. Jung, Scripta Material, 49, 2003, p.423.
35. L. Karlsson, E. L. Bergqvist, and H. Larsson, Eorojoin 4, Dubrovik-Cavtat, May, 2001, p.24.
36. K. V. Jata and S. L. Semiatin, "Continuous Dynamic Recrystallization during Friction Stir Welding of High Strength Aluminum Alloys", Scripta Material, Vol. 43, 2000, pp.743-749.
37. K. V. Jata, K. K. Sankaran, and J. J. Ruschau, "Friction-Stir Welding Effects on Microstructure and Fatigue of Alumium Alloy 7050-T7451", Metall. & Mater. Trans., Vol. 31A, 2000, pp.2181-2192.
38. A. Denquin, D. Allehaux, M. H. Campagnac, and G. Lapasset, Mater. Sci. Forum, 2921, 2003, pp.426-432.
39. G. Oertelt, S. S. Babu, S. A. David, and E. A. Kenik, "Effect of Thermal Cycling on Friction Stir Welds of 2195 Aluminum Alloy", Welding J., March 2001, pp.71-79.
40. Aluminium Frederation, "The properties of aluminium and its alloys", Alfed, 1983.
41. O. T. Midling, E. J. Morley, and A. Sandvik, "Friction stir welding", World Intellectual Property Orqanization WO95/26254, (1995) (EP0752926).
42. 啟學編輯部編譯，鋁合金資料集，啟學出版社，(1989) pp.30.
43. P. J. Ditzel and J. C. Lippold, "Microstructure/property relationships in alumimum friction stir welds", Materials Jioning Technology, EWI Report, Aug. 1999, pp.108-110.