بررسی اثر روی بر ریزساختار و رفتار انجمادی آلیاژهای Al-Zn-Mg-Cu

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناسی ارشد، دانشکده مهندسی متالورژی و مواد، پردیس دانشکده‌های فنی دانشگاه تهران، دانشگاه تهران،

2 استادیار، دانشکده مهندسی متالورژی و مواد، پردیس دانشکده‌های فنی دانشگاه تهران، دانشگاه تهران،

3 استاد، دانشکده مهندسی متالورژی و مواد، پردیس دانشکده‌های فنی دانشگاه تهران، دانشگاه تهران،

چکیده

در این پژوهش اثر روی بر ریزساختار و رفتار انجمادی آلیاژ فوق مستحکم جدید Al-Zn-Mg-Cu مورد مطالعه قرار گرفت. به منظور مطالعات انجمادی از آنالیز حرارتی منحنی سرمایش استفاده شد. این روش رفتار انجمادی آلیاژ را با دقت مناسب و سرعت بالایی در اختیار قرار می‌دهد. مطالعات ریزساختاری نشان داد که افزایش در میزان روی منجر به افزایش فاصله بازوهای دندریتی، افزایش کسر حجمی فاز‌های ثانویه و ساختار یوتکتیک و تشکیل دندریت‌های خشن و درشت شده است، با این حال افزایش درمیزان روی اثری بر نوع فازهای ثانویه تشکیل شده نداشته است. در مطالعات آنالیز حرارتی، حضور روی منجر به کاهش دمای جوانه زنی شد. به کمک منحنی سرمایش، تشکیل یک فاز در مراحل میانی انجماد مشاهده شد که می‌تواند فاز حاوی آهن Al13Fe4 باشد. دامنه انجمادی در 8 درصد وزنی روی 175 درجه سلسیوس بود که با افزایش روی تا 25 درصد این دامنه به 190 درجه سلسیوس افزایش یافت. با مقایسه نتایج به دست آمده مشاهده شد که افزایش کسر حجمی فازهای ثانویه با افزایش روی در نتایج آنالیز حرارتی و آنالیز تصویری در تطابق بود. همچنین کسر انجماد یافته در نقطه کوهیرنسی دندریتها از 32/0 به 1/0 درصد کاهش یافت که با افزایش در میزان تخلخل از 09/0 به 32/0 در تطابق است.

کلیدواژه‌ها


عنوان مقاله [English]

The effect of zinc on microstructure and solidification characteristics of Al-Zn-Mg-Cu alloys

نویسندگان [English]

  • Saman Mostafapoor 1
  • Mehdi Malekan 2
  • Masoud Emamy 3
1 MSc, Metallurgy and Materials Engineering, School of Metallurgy and Materials Engineering,University of Tehran,
2 Assistant Professor, Metallurgy and Materials Engineering, School of Metallurgy and Materials Engineering,University of Tehran,
3 Professor, Metallurgy and Materials Engineering, School of Metallurgy and Materials Engineering,University of Tehran,
چکیده [English]

In this study, the effect of zinc on microstructure and solidification characteristics of super high strength Al-Zn-Mg-Cu has been investigated. The solidification studies were performed using cooling curve thermal analysis. This method represents quick and accurate results of solidification path of an alloy. The microstructure studies showed increment in the amounts of zinc increases the dendrite arm spacing (DAS), fraction of second phases and eutectic structure and results in a coarse dendrite structure. However, the zinc content did not affect the present phases in this alloying system. Thermal analysis evaluations revealed decrease in nucleation temperature with zinc addition. The formation of Al13Fe4 phase was observed using by cooling curve. The solidification range in the presence of 8wt.% of zinc was 175 °C although the adding of zinc up to 25 wt.% increased it to 190 °C. Cooling curves represented the increase of the fraction of eutectic structure which was in accordance with image analysis results. The addition of zinc resulted in the decrease of the solidified fraction at dendrite coherency point from 0.32 to 0.1 which matched by increment in porosity fraction from 0.09 to 0.32.

کلیدواژه‌ها [English]

  • Al-Zn-Mg-Cu alloy
  • Solidification
  • Thermal analysis
  • Cooling curve
  • microstructure
1. Gao T, Zhang Y, Liu X. Influence of trace Ti on the microstructure, age hardening behavior and mechanical properties of an Al-Zn-Mg-Cu-Zr alloy. Mater Sci Eng A. 2014;598:293–8.
2. Deng Y, Yin Z, Zhao K, Duan J, Hu J, He Z. Effects of Sc and Zr microalloying additions and aging time at 120°C on the corrosion behaviour of an Al–Zn–Mg alloy. Corros Sci. 2012;65:288–98.
3. Fang HC, Chao H, Chen KH. Effect of Zr, Er and Cr additions on microstructures and properties of Al-Zn-Mg-Cu alloys. Mater Sci Eng A. 2014;610:10–6.
4. Wu YL, Froes FH, Alvarez A, Li CG, Liu J. Microstructure and properties of a new super-high-strength Al-Zn-Mg-Cu alloy C912. Mater Des. 1998;18:211–5.
5. Pourkia N, Emamy M, Farhangi H, Ebrahimi SHS. The effect of Ti and Zr elements and cooling rate on the microstructure and tensile properties of a new developed super high-strength aluminum alloy. Mater Sci Eng A. 2010;527:5318–25.
6. Seyed Ebrahimi SH, Emamy M. Effects of Al–5Ti–1B and Al–5Zr master alloys on the structure, hardness and tensile properties of a highly alloyed aluminum alloy. Mater Des. 2010;31:200–9.
7. Seyed Ebrahimi SH, Emamy M, Pourkia N, Lashgari HR. The microstructure, hardness and tensile properties of a new super high strength aluminum alloy with Zr addition. Mater Des. 2010;31:4450–6.
8. Fan Z, Wang Y, Zhang Y, Qin T, Zhou XR, Thompson GE, et al. Grain refining mechanism in the Al/Al–Ti–B system. Acta Mater. 2015;84:292–304.
9. Easton M, Stjohn D. Grain refinement of aluminum alloys: Part I. The nucleant and solute paradigms - a review of the literature. Metall Mater Trans A Phys Metall Mater Sci. 1999;30:1613–23.
10. Chen K, Liu H, Zhang Z, Li S, Todd RI. The improvement of constituent dissolution and mechanical properties of 7055 aluminum alloy by stepped heat treatments. J Mater Process Technol. Elsevier; 2003;142:190–6.
11. Stefanescu DM. Science and engineering of casting solidification: Third edition. Sci. Eng. Cast. Solidif. Third Ed. 2015.
12. Shabestari SG, Malekan M. Assessment of the effect of grain refinement on the solidification characteristics of 319 aluminum alloy using thermal analysis. J Alloys Compd. 2010;492:134–42.
13. Naghdali S, Jafari H, Malekan M. Cooling curve thermal analysis and microstructure characterization of Mg-5Zn-1Y-xCa (0–1 wt%) alloys. Thermochim Acta. 2018;667:50–8.
14. Mostafapoor S, Malekan M, Emamy M. Thermal analysis study on the grain refinement of Al–15Zn–2.5Mg–2.5Cu alloy. J Therm Anal Calorim [Internet]. 2017;127:1941–52. Available from: https://doi.org/10.1007/s10973-016-5737-7
15. Upadhya KG, Stefanescu DM, Lieu K, Yeager DP. Computer-aided cooling curve analysis: principles and applications in metal casting. AFS Trans. 1989. p. 1989.
16. Larranaga P, Gutierrez JM, Loizaga  a, Sertucha J, Suarez R. A Computer-Aided System for Melt Quality and Shrinkage Propensity Evaluation Based on the Solidification Process of Ductile Iron. Trans Am Foundry Soc. 2008;
17. Emadi D, Whiting L V, Đurđević MB, Kierkus WT, Sokolowski J. Comparison of newtonian and fourier thermal analysis techniques for calculation of latent heat and solid fraction of aluminum alloys. Metalurgija. 2004;10:91–106.
18. Hegde S, Prabhu KN. Modification of eutectic silicon in Al-Si alloys. J Mater Sci. 2008;
19. Ludwig TH, Schaffer PL, Arnberg L. Influence of some trace elements on solidification path and microstructure of Al-Si foundry alloys. Metall Mater Trans A Phys Metall Mater Sci. 2013;
20. Shin J, Lee Z, Ul-Haq I. Computer-Aided Cooling Curve Analysis of A356 Aluminum Alloy. Met Mater Int. 2004;10:89–96.
21. Eguskiza S, Niklas A, Fernández-Calvo AI, Santos F, Djurdjevic M. Study of strontium fading in Al-Si-Mg and Al-Si-Mg-Cu alloy by thermal analysis. Int J Met. 2015;9:43–50.
22. Coniglio N, Cross CE. Characterization of solidification path for aluminium 6060 weld metal with variable 4043 filler dilution. Weld World. 2006. p. 14–23.
23. Ghoncheh MH, Shabestari SG, Abbasi MH. Effect of cooling rate on the microstructure and solidification characteristics of Al2024 alloy using computer-aided thermal analysis technique. J Therm Anal Calorim. 2014;117:1253–61.
24. Kamguo Kamga H, Larouche D, Bournane M, Rahem A. Solidification of aluminum-copper B206 alloys with iron and silicon additions. Metall Mater Trans A Phys Metall Mater Sci. 2010;
25. Haghdadi N, Phillion AB, Maijer DM. Microstructure Characterization and Thermal Analysis of Aluminum Alloy B206 During Solidification. Metall Mater Trans A Phys Metall Mater Sci. 2015;46:2073–81.
26. Farahany S, Ourdjini A, Idris MH, Shabestari SG. Computer-aided cooling curve thermal analysis of near eutectic Al – Si – Cu – Fe alloy. J Therm Anal Calorim. 2013;114:1–13.
27. Farahany S, Idris MH, Ourdjini A, Faris F, Ghandvar H. Evaluation of the effect of grain refiners on the solidification characteristics of an Sr-modified ADC12 die-casting alloy by cooling curve thermal analysis. J Therm Anal Calorim. 2015;
28. Malekan M, Dayani D, Mir A. Thermal analysis study on the simultaneous grain refinement and modification of 380.3 aluminum alloy. J Therm Anal Calorim. 2014;
29. Timelli G, Camicia G, Ferraro S. Effect of grain refinement and cooling rate on the microstructure and mechanical properties of secondary Al-Si-Cu alloys. J Mater Eng Perform. 2014;
30. Gonzalez C, Alvarez O, Genesca J, Juarez-Islas JA. Solidification of chill-cast Al-Zn-Mg alloys to be used as sacrificial anodes. Metall Mater Trans A Phys Metall Mater Sci. 2003;34:2991–7.
31. Ahmad AH, Naher S, Brabazon D. Thermal profiles and fraction solid of aluminium 7075 at different cooling rate conditions. Key Eng Mater. Trans Tech Publ; 2013. p. 582–95.
32. Dahle AK, Arnberg L. Development of strength in solidifying aluminium alloys 10.1016/S1359-6454(96)00203-0 : Acta Materialia | ScienceDirect.com. Acta Mater [Internet]. 1997;45:547–59. Available from: http://www.sciencedirect.com/science/article/pii/S1359645496002030
33. Backerud L, Chai G, Tamminen J. Solidification Characteristics of Aluminum Alloys. Vol. 2. Foundry Alloys. AFS/SkanAluminum. 1990;266.
34. Alipour M, Emamy M. Effects of Al–5Ti–1B on the structure and hardness of a super high strength aluminum alloy produced by strain-induced melt activation process. Mater Des. 2011;32:4485–92.
35. Djurdjevič MB, Grzinčič MA. The Effect of Major Alloying Elements on the Size of Secondary Dendrite Arm Spacing in the As-Cast Al-Si-Cu Alloys. Arch Foundry Eng. 2012;12:19–24.
36. Mishra RR, Sharma AK. Effect of susceptor and mold material on microstructure of in-situ microwave casts of Al-Zn-Mg alloy. Mater Des. 2017;131:428–40.
37. Jiang W, Jiang Z, Li G, Wu Y, Fan Z. Microstructure of Al/Al bimetallic composites by lost foam casting with Zn interlayer. Mater Sci Technol. Taylor & Francis; 2018;34:487–92.
38. Mostafapoor S, Malekan M, Emamy M. Effects of Zr addition on solidification characteristics of Al–Zn–Mg–Cu alloy using thermal analysis. J Therm Anal Calorim. Springer; 2018;134:1457–69.
39. Liu JT, Zhang YA, Li XW, Li ZH, Xiong BQ, Zhang JS. Thermodynamic calculation of high zinc-containing Al-Zn-Mg-Cu alloy. Trans Nonferrous Met Soc China (English Ed. 2014;
40. Xie F, Yan X, Ding L, Zhang F, Chen S, Chu MG, et al. A study of microstructure and microsegregation of aluminum 7050 alloy. Mater Sci Eng A. 2003;
41. Mondal C, Mukhopadhyay AK. On the nature of T(Al2Mg3Zn3) and S(Al2CuMg) phases present in as-cast and annealed 7055 aluminum alloy. Mater Sci Eng A. 2005;
42. Timelli G, Caliari D. Effect of Superheat and Oxide Inclusions on the Fluidity of A356 Alloy. Mater Sci Forum [Internet]. Trans Tech Publ; 2017. p. 71–80. Available from: http://www.scientific.net/MSF.884.71
43. Yang L, Li W, Du J, Wang K, Tang P. Effect of Si and Ni contents on the fluidity of Al-Ni-Si alloys evaluated by using thermal analysis. Thermochim Acta. 2016;645:7–15.
44. Arnberg L, Chai G, Backerud L. Determination of dendritic coherency in solidifying melts by rheological measurements. Mater Sci Eng A. 1993;173:101–3.
45. Malekan M, Shabestari SG. Effect of grain refinement on the dendrite coherency point during solidification of the A319 aluminum alloy. Metall Mater Trans A. 2009;40:3196–203.