7xxx系鋁合金例如7075與7050鋁合金因具有高強度、良好破壞韌性及抗應力腐蝕能力等優點，適合應用於航太及汽車工業。管材可經由塑性加工成所需產品形狀，成型性佳的材料通常必須具備高均勻變形能力及低異向性等特徵，目前主要以7075鋁合金為材料。本實驗以具有超高強度之7001鋁合金管材為材料，除了工業常用之較耗時退火處理(O材)，也使用固溶化處理(W材)改善延性以符合塑性加工成型應用。本研究比較兩熱處理對拉伸性質的影響，並評估管材性質之異向性。
本次實驗以退火(O: 415℃緩慢冷卻至260℃在爐冷至室溫)以及固溶化處理(W: 490℃持溫接著水淬)作為兩條件，並測試平行與垂直方向之拉伸性質。實驗結果顯示，O材與W材在強度與延性上兩方向的差異性皆不顯著，第二相顆粒排列與基地織構會影響管材兩方向之拉伸性質。退火軟化材料的效果較固溶化處理大，O材降伏與抗拉強度皆只有W材的一半，延性方面，W材具有較大均勻變形量，推測為晶出相與析出強化相固溶回基地，使基地呈過飽合狀態，在拉伸時發生動態應變時效使加工硬化率提高，並且大致以剪切破壞為主要機制；O材組織中有大量晶出相及MgZn2相，拉伸變形時裂縫易於晶出相形成及合併導致較大不均勻變形，推斷傾向延性破壞為主。固溶化處理雖然軟化效果不如退火處理，但能使加工硬化率大幅提升，因此有較大均勻變形量，此特性可推斷固溶化處理相對退火處理有較佳提升成型性效果，然而此法會受到自然時效效應之限制。

7001 aluminum alloy tube has higher strength but lower ductility in Al-Zn-Mg-Cu alloy system. Heat treatments are conducted to improve formability before plastic process. Annealing―415℃/2h→260℃/2h→RT(by furnace cooling) and solution treatment―490℃→RT(by water quenching) were used in this study. Microstructure observation by OM and SEM, phase analysis by XRD and DSC, and tensile tests were done. Properties of parallel and vertical to extrusion direction were investigated respectively. As the results showed, microstructure (alignment of particles and texture) affected the tensile properties, but no obvious difference of tensile properties between two directions. After annealing, Al matrix became soft and second phases particles remained, which caused low strength and high ductility. The major fracture mode was ductile fracture, and dimple distributed throughout the fracture surface. After solution treatment, most second phases dissolved into matrix, leading to supersaturated state of material. During deformation, it showed high work hardening rate and exhibited larger uniform elongation than annealing treated one, and it ruptured in shear fracture mode. As a whole, solution treatment had a bigger benefit of improving formability before plastic process.

第六章 參考文獻
1. Clinch M.R., Harris, S.J., Hepples, W., Holroyd, N.J.H., Lawday, M.J., Noble, B., Influence of zinc to magnesium ratio and total solute content on the strength and toughness of 7xxx series alloys, in Aluminium Alloys 2006, Pts 1 and 2: Research through Innovation and Technology, W.J. Poole, M.A. Wells, and D.J. Lloyd, Editors. 2006, Trans Tech Publications Ltd: Zurich-Uetikon. pp. 339-344.
2. Tajally, M., Huda Z., Masjuki, H.H., A comparative analysis of tensile and impact-toughness behavior of cold-worked and annealed 7075 aluminum alloy. International Journal of Impact Engineering, 2010. 37(4): pp. 425-432.
3. Deschamps, A., Niewczas, M.,Bley, F.,Brechet. Y.,Embury, J.D.,Le Sinq, L.,Livet, F.,Simon, J.P., Low-temperature dynamic precipitation in a supersaturated Al-Zn-Mg alloy and related strain hardening. Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties, 1999. 79(10): pp. 2485-2504.
4. Chen Z., Mo, Y., Nie, Z., Effect of Zn Content on the Microstructure and Properties of Super-High Strength Al-Zn-Mg-Cu Alloys. Metallurgical and Materials Transactions A, 2013. 44(8): pp. 3910-3920.
5. Deng, Y.L.,Wan, L., Zhang, Y.Y., Zhang, X.M., Influence of Mg content on quench sensitivity of Al-Zn-Mg-Cu aluminum alloys. Journal of Alloys and Compounds, 2011. 509(13): pp. 4636-4642.
6. Fatemi, A., Morovvati, M.R., Biglari, F.R., The effect of tube material, microstructure, and heat treatment on process responses of tube hydroforming without axial force. International Journal of Advanced Manufacturing Technology, 2013. 68(1-4): pp. 263-276.
7. Koc, M., Altan, T., An overall review of the tube hydroforming (THF) technology. Journal of Materials Processing Technology, 2001. 108(3): pp. 384-393.
8. Lee, M.Y., Sohn, S.M., Kang, C.Y., Suh, D.W., Lee, S.Y., Effects of pre-treatment conditions on warm hydroformability of 7075 aluminum tubes. Journal of Materials Processing Technology, 2004. 155: pp. 1337-1343.
9. Poole, W.J., Saeter, J.A., Skjervold, S., Waterloo, G., A model for predicting the effect of deformation after solution treatment on the subsequent artificial aging behavior of AA7030 and AA7108 alloys. Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science, 2000. 31(9): pp. 2327-2338.
10. Chinh, N.Q., , The effect of Cu on mechanical and precipitation properties of AI-Zn-Mg alloys. Journal of Alloys and Compounds, 2004. 378(1-2): pp. 52-60.
11. Rometsch, P.A., Zhang, Y., Knight, S., Heat treatment of 7xxx series aluminium alloys—Some recent developments. Transactions of Nonferrous Metals Society of China, 2014. 24(7): pp. 2003-2017.
12. Srivatsan, T.S., An investigation of the cyclic fatigue and fracture behavior of aluminum alloy 7055. Materials & Design, 2002. 23(2): pp. 141-151.
13. Hadjadj, L., Amira, R., The effect of Cu addition on the precipitation and redissolution in Al–Zn–Mg alloy by the differential dilatometry. Journal of Alloys and Compounds, 2009. 484(1–2): pp. 891-895.
14. Lin, F.S., Starke Jr, E.A., The effect of copper content and degree of recrystallization on the fatigue resistance of 7XXX type aluminum alloys I. Low cycle corrosion fatigue. Materials Science and Engineering, 1979. 39(1): pp. 27-41.
15. Sarkar, B., Marek, M., Starke, E.A., The effect of copper content and heat treatment on the stress corrosion characteristics of Al-6Zn-2Mg-X Cu alloys. Metallurgical Transactions A, 1981. 12(11): pp. 1939-1943.
16. Speidel, M., Stress corrosion cracking of aluminum alloys. Metallurgical Transactions A, 1975. 6(4): pp. 631-651.
17. Speidel, M.O., STRESS-CORROSION CRACKING OF ALUMINUM-ALLOYS. Metallurgical Transactions, 1975. A 6(4): pp. 631-651.
18. Deshpande, N.U., Goahale, A.M., Denzer, D.K., Liu, J., Relationship between fracture toughness, fracture path, and microstructure of 7050 aluminum alloy: Part I. Quantitative characterization. Metallurgical and Materials Transactions Physical Metallurgy and Materials Science, 1998. 29(4): pp. 1191-1201.
19. Li, X.M., Starink, M.J., Identification and analysis of intermetallic phases in overaged Zr-containing and Cr-containing Al-Zn-Mg-Cu alloys. Journal of Alloys and Compounds, 2011. 509(2): pp. 471-476.
20. Zou, L., Pan, Q.L., He, Y.B., Wang, C.Z., Liang, W.J., Effect of minor Sc and Zr addition on microstructures and mechanical properties of Al-Zn-Mg-Cu alloys. Transactions of Nonferrous Metals Society of China, 2007. 17(2): pp. 340-345.
21. Li, X.M., Starink, M.J., DSC Study on Phase Transitions and Their Correlation with Properties of Overaged Al-Zn-Mg-Cu Alloys. Journal of Materials Engineering and Performance, 2012. 21(6): pp. 977-984.
22. Maloney, S.K., Hono, K., Polmear, I.J., Ringer, S.P., The chemistry of precipitates in an aged Al-2.1Zn-1.7Mg at.% alloy. Scripta Materialia, 1999. 41(10): pp. 1031-1038.
23. Li, X.M., Starink, M.J., Effect of compositional variations on characteristics of coarse intermetallic particles in overaged 7000 aluminium alloys. Materials Science and Technology, 2001. 17(11): pp. 1324-1328.
24. Li, Y.Y., Kovarik, L., Phillips, P.J., Hsu, Y.F., Wang, W.H., Mills, M.J., High-resolution characterization of the precipitation behavior of an Al-Zn-Mg-Cu alloy. Philosophical Magazine Letters, 2012. 92(4): pp. 166-178.
25. Sha, G., Cerezo, A., Characterization of precipitates in an aged 7xxx series Al alloy. Surface and Interface Analysis, 2004. 36(5-6): pp. 564-568.
26. Leacock, A.G., Howe, C., Brown, D., Lademo, O.G., Deering, A., Evolution of mechanical properties in a 7075 Al-alloy subject to natural ageing. Materials & Design, 2013. 49: pp. 160-167.
27. Xu, D.K., Rometsch, P.A., and N. Birbilis, Improved solution treatment for an as-rolled Al-Zn-Mg-Cu alloy. Part II. Microstructure and mechanical properties. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2012. 534: pp. 244-252.
28. Xu, D.K., P.A. Rometsch, Birbilis, N., Improved solution treatment for an as-rolled Al-Zn-Mg-Cu alloy. Part I. Characterisation of constituent particles and overheating. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2012. 534: pp. 234-243.
29. 金重勳, 熱處理. 民國74年: pp. 473-474.
30. Westermann, I., Pedersen, K.O., Furu, T., Borvil, T. , Hopperstad, O.S., Effects of particles and solutes on strength, work-hardening and ductile fracture of aluminium alloys. Mechanics of Materials, 2014. 79: pp. 58-72.
31. Cheng, L.M., Poole, W.J., Embury, J.D., Lloyd, D.J., The influence of precipitation on the work-hardening behavior of the aluminum alloys AA6111 and AA7030. Metallurgical and Materials Transactions Physical Metallurgy and Materials Science, 2003. 34A(11): pp. 2473-2481.
32. Cubberly, W.H., Craig W, V.M.,. Kirkpatrick, Bonnie Sanders, Metals Handbook Ninth Edition Volume 4 Heat Treating. 1981. 4: pp. 707-708.
33. T. Wang, Z.M.Y., Sun, Q., Trans. Nonferrous Met. 2007. China 17 pp. 335-339.
34. Equilibrium Diagrams of Aluminium Alloy Systems. 1961: pp. 54.
35. Massalski, C.S.B.a.T.B., Structure of Metals. 1980: Mcgraw-Hill Inc. pp.203-205.
36. Panigrahi, S.K., Jayaganthan, R., Effect of Annealing on Thermal Stability, Precipitate Evolution, and Mechanical Properties of Cryorolled Al 7075 Alloy. Metallurgical and Materials Transactions a-Physical Metallurgy and Materials Science, 2011. 42A(10): pp. 3208-3217.
37. Kumar, M., Poletti, C., Degischer, H.P., Precipitation kinetics in warm forming of AW-7020 alloy. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2013. 561: pp. 362-370.
38. Buha, J., Lumley, R.N., Crosky, A.G., Secondary ageing in an aluminium alloy 7050. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2008. 492(1-2): pp. 1-10.
39. Davies, C.H.J., N. Raghunathan, and T. Sheppard, Investigation of Mechanical-Properties of Advanced Al-Zn-Mg-Cu Alloy. Materials Science and Technology, 1992. 8(10): pp. 862-868.
40. Kobayashi, T., Strength and fracture of aluminum alloys. Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing, 2000. 280(1): pp. 8-16.
41. Jiang, D.M., Wang, C.L., Yu, J., Gao, Z.Z., Shao, Y.T., Hu, Z.M., Cleavage and intergranular fracture in Al-Mg alloys. Scripta Materialia, 2003. 49(5): pp. 387-392.
42. Dumont, D., Deschamps, A., Brechet, Y., A model for predicting fracture mode and toughness in 7000 series aluminium alloys. Acta Materialia, 2004. 52(9): pp. 2529-2540.
43. Roven, H.J., A Model For Fracture-Toughness Predictions in Aluminum-Alloys Exhibiting The Slip Band Decohesion Mechanism. Scripta Metallurgica Et Materialia, 1992. 26(9): pp. 1383-1388.
44. 李信委, 摩擦攪拌製程對AZ31鎂合金擠型材微觀組織及拉伸性質之影響. 國立成功大學材料科學與工程學系博士論文, 2012.,pp.11.