AA7075-T6 ve AZ31B Alaşımlarının Sürtünme Karıştırma Kaynağı Üzerinde Ön Isıtma ve Kuru Buz Soğutmasının Etkisi

Abstract

Bu çalışmada, AA7075­T6 alüminyum ve AZ31B magnezyum alaşımlarının sürtünme karıştırma kaynak (SKK) yöntemi ile kaynak edilebilme özelliği araştırılmıştır. Farklı kimyasal ve mekanik özelliklere sahip alüminyum ve magnezyum alaşımlarını sürtünme karıştırma kaynağı ile birleştirebilmek için sabit devir, sabit tabla ilerleme hızı, farklı takım kaydırma değerlerinde, numunelere ön ısıtma ve kuru buz ile soğutma işlemleri uygulanarak dört farklı kaynak işlemi yapılmıştır. Birleştirilmiş numunelerin kaynak kalitesi, tahribatlı ve tahribatsız muayene yöntemleri kullanılarak değerlendirilmiştir. Alüminyum alaşımına uygulanan ön ısıtmanın ve kaynak işlemi sırasında uygulanan kuru buz ile soğutmanın mekanik ve mikro yapısal özellikler üzerindeki etkisi incelenmiştir. Test sonuçları, önceden ısıtılmış ve kaynak işlemi sırasında kuru buz ile soğutulmuş kaynaklı numunelerinin çekme dayanımının daha yüksek olduğunu göstermiştir. Ön ısıtma işlemine tabi tutulmuş numunelerin kaynak yüzeyinde gözenek oluşumu görülürken, kuru buz ile soğutma yapılarak birleştirilen numunenin kaynak hattında boşluk oluşumu gözlenmiştir. Normal kaynaklı numunelere kıyasla, ön ısıtma ve kuru buz soğutma işlemine tabi tutularak birleştirilmiş numunelerin karıştırma bölgesinde homojen bir karışım elde edilmiştir. 

Keywords

• AA7075,AZ31B,sürtünme karıştırma kaynağı,ön ısıtma,kuru buz soğutma,mekanik özellikler,mikro yapı

Effect of Preheating and Dry Ice Cooling on Dissimilar Friction Stir Welding of AA7075-T6 and AZ31B

Abstract

In this study, dissimilar friction stir welding behavior of AA7075-T6 aluminum and AZ31B magnesium alloys were investigated. Aluminum and magnesium alloys were joined by friction stir welding under four welding conditions and in two environments, namely pre-heated aluminum and dry ice for cooling, with tool rotation of 1120 rpm, table speed of 20 mm/min and two different tool offset values. The welding quality of the joined specimens were evaluated by employing destructive and non-destructive testing methods. The influence of the pre-heating applied to the aluminum alloy and employing ice cooling during the welding process on the mechanical and microstructural properties were examined. The test results showed that the higher tensile strength values were obtained from welded specimens of the pre-heated and cooled by dry ice during the welding process. Porosities were seen on the welded surface of the pre-heated specimen while the cavities were observed on the joint line of the cooled specimen using dry ice during the process. A homogenous material mixing was achieved in the stir zone of the welded specimens subjected to pre-heating and dry ice cooling process compared with the normal welded specimens.

Keywords

• AA7075,AZ31B,friction stir welding,pre-heating,dry ice cooling,mechanical properties,microstructure

References

1. [1] Dorbane A., Mansoor B., Ayoub G., Shunmugasamy V.C. and Imad A., “Mechanical, microstructural and fracture properties of dissimilar welds produced by friction stir welding of AZ31B and Al6061”, Mater. Sci. Eng. A., 651:720–733, (2016)
2. [2] Liu L., Ren D. and Liu F., “A review of dissimilar welding techniques for magnesium alloys to aluminum alloys”, Materials (Basel), 7: 3735–3757, (2014)
3. [3] Liu P. and Li Y., Geng H., Wang J., “Microstructure characteristics in TIG welded joint of Mg/Al dissimilar materials”, Mater. Lett., 61: 1288–1291, (2007)
4. [4] Ben-Artzy A., Munitz A., Kohn G., Bronfin B. ans Shtechman A., “Joining of light hybrid constructions made of magnesium and aluminum alloys”, TMS Annual Meeting, 295–302, (2002)
5. [5] Chi C.T., Chao C.G., Liu T.F. and Lee C.H., “Aluminum element effect for electron beam welding of similar and dissimilar magnesium–aluminum–zinc alloys”, Scr. Mater., 56: 733–736, (2007)
6. [6] Bannour S., Abderrazak K., Mattei S., Masse J.E., Autric M., Mhiri H., “The influence of position in overlap joints of Mg and Al alloys on microstructure and hardness of laser welds”, J. Laser Appl., 25: 032001- 032008, (2013)
7. [7] Thomas W., Nicholas E., Needham J., Murch M., Temple-Smith P. and C. Dawes, Friction stir butt welding, International Patent No. PCT/GB92/02203, GB Patent No. 9125978.8, 1991, U.S. Patent No. 5,460,317, (1995)
8. [8] Cam G., ”Friction stir welded structural materials: beyond Al-alloys”, International Materials Reviews, 56(1): 1-48, (2011)

9. [9] Mohammadi J., Behnamian Y., Mostafaei A., Izadi H., Saeid T., Kokabi A.H. and Gerlich A.P., “Friction stir welding joint of dissimilar materials between AZ31B magnesium and 6061 aluminum alloys: Microstructure studies and mechanical characterizations”, Materials Characterization, 101: 189–207, (2015)
10. [10] Zhao Y., Lu Z., Yan K. and Huang L., “Microstructural characterizations and mechanical properties in underwater friction stir welding of aluminum and magnesium dissimilar alloys”, Materials and Design, 65: 675–681, (2015)
11. [11] Venkateswaran P. and Reynolds A.P., “Factors affecting the properties of friction stir welds between aluminum and magnesium alloys”, Material. Sci. and Eng., A545: 26– 37, (2012)
12. [12] Jagadeesha C.B., “Dissimilar friction stir welding between aluminum alloy and magnesium alloy at a low rotational speed”, Material. Sci.and Eng., A616: 55–62, (2015)
13. [13] Masoudian A., Tahaei A., Shakiba A., Sharifianjazi F., and Mohandesi J.A., “Microstructure and mechanical properties of friction stir weld of dissimilar AZ31-O magnesium alloy to 6061-T6 aluminum alloy”, Trans. Nonferrous Met. Soc. China, 24: 1317−1322, (2014)
14. [14] Tabasi M., Farahani M., Besharati Givi M. K., Farzami M., and Moharami A., “Dissimilar friction stir welding of 7075 aluminum alloy to AZ31 magnesium alloy using SiC nanoparticles”, Int J Adv Manuf Technol. , 86(1-4): 705 – 715, (2015)
15. [15] Ji S., Meng X., Liu Z., Huang R. and Li Z., “Dissimilar friction stir welding of 6061 aluminum alloy and AZ31 magnesium alloy assisted with ultrasonic”, Mater Lett., 201: 173–176, (2017)
16. [16] Hou Z., Sheikh-Ahmad J., Jarrar F. and Ozturk F., “Residual stresses in dissimilar friction stir welding of AA2024 and AZ31: experimental and numerical study”, J Manuf Sci Eng., 140: 1–10, (2018)
17. [17] Hernández-García D., Saldaña-Garcés R., García-Vázquez F., Gutiérrez-Castañeda E.J., Deaquino-Lara R. and Verdera D., “Friction stir welding of dissimilar AA7075-T6 to AZ31B-H24 alloys”, MRS Advances, 2(64): 1-9, (2017)
18. [18] Ratna Sunil B., Pradeep Kumar Reddy G., Mounika A.S.N, Navya Sree P., Rama Pinneswari P., Ambica I., Ajay Babu R. and Amarnadh P., “Joining of AZ31 and AZ91 Mg alloys by friction stir welding”, J Magnes Alloy, 3 (4): 330–334, (2015)
19. [19] Çevik B., “Sürtünme karıştırma kaynak parametrelerinin kalıntı gerilmelere ve birleştirmenin mekanik özelliklerine etkisi, Doktora, Gazi Üniversitesi Fen Bilimleri Enstitüsü, (2014)
20. [20] Çevik B., Özçatalbaş Y. and Gülenç B., “Friction stir welding of 7075-T651 aluminium alloy”, Practical Metallography, 53(1): 6-23, (2016)
21. [21] Buffa G., Campanella D. and Fratini L., “Enhancement of mechanical properties of FSWed AA7075 lap joints through in-situ fabrication of MMC”, J. Manuf. Process., 28: 422–427, (2016)
22. [22] Mofid M.A., Abdollah-Zadeh A. and Gür C.H., “Investigating the formation of intermetallic compounds during friction stir welding of magnesium alloy to aluminum alloy in air and under liquid nitrogen”, Int. J. Adv. Manuf. Technol., 71: 1493–1499, (2014)
23. [23] Mofid M.A., Abdollah-zadeh A., Malek Ghaini F., “The effect of water cooling during dissimilar friction stir welding of Al alloy to Mg alloy”, Mater. Des., 36: 161–167, (2012)
24. [24] İpekoğlu G. and Çam G., “Effects of initial temper condition and postweld heat treatment on the properties of dissimilar friction-stir-welded joints between AA7075 and AA6061 aluminum alloys”, Metallurgical and Materials Trans. A, 45(7): 3074-3087, (2014)
25. [25] İpekoğlu G., Erim S. and Çam G. “Effects of temper condition and post weld heat treatment on the microstructure and mechanical properties of friction stir butt-welded AA7075 Al alloy plates”, The Int. Journal of Adv. Man. Tech., 70(1-4): 201-213, (2014)
26. [26] Simoncini M. and Forcellese A., “Effect of the welding parameters and tool configuration on micro- and macro-mechanical properties of similar and dissimilar FSWed joints in AA5754 and AZ31 thin sheets”, Materials and Design, 41:50–60, (2012)
27. [27] Yang Y. K., Dong H., Cao H., Chang Y. A., and Kou S. “Liquation of Mg alloys in friction-stir spot welding”, Welding Journal, 87: 167-177, (2008)
28. [28] Yamamoto N., Liao J., Watanabe S. and Nakata K., “Effect of intermetallic compound layer on tensile strength of dissimilar friction-stir weld of a high strength Mg alloy and Al alloy”, Materials Transactions, 50 (2): 2833-2838, (2009)
29. [29] Fırouzdor V. and Kou S., “Al-to-Mg friction stir welding: effect of material position, travel speed and rotation speed”, Metal. and Mat. Trans. A, 41A: 2914-2935, (2010)
30. [30] Azizieh M., Alavijeh A. S., Abbasi M., Balak Z. and Kim H.S., “Mechanical properties and microstructural evaluation of AA1100 to AZ31 dissimilar friction stir welds”, Materials Chemistry and Physics, 170: 251-260, (2016)
31. [31] Fırouzdor V. and Kou S., “Al-to-Mg friction stir welding: effect of positions of Al and Mg with respect to the welding tool”, The Welding Journal, 88: 213-224, (2009)
32. [32] Yutaka S. S., Park S. H. C., Masato M. and Hiroyuki K., “Constitutional liquation during dissimilar friction stir welding of Al and Mg alloys”, Scripta Mater, 50(9): 1233–1236, (2004)
33. [33] Yang Y. K., Dong H. and Kou S., “Liquation tendency and liquid-film formation in friction stir spot welding”, Welding Journal, 87 (8): 202-211, (2008)
34. [34] Sarsılmaz F., “Sürtünme karıştırma kaynak yöntemi ile birleştirilmiş AA7075/AA6061 kaynaklı bağlantıların mikroyapı ve mekanik özelliklerinin araştırılması”, Doktora, Fırat Üniversitesi Fen Bilimleri Enstitüsü, (2008).
35. [35] Yan Y., Zhang D., Qiu C. and Zhang W., “Dissimilar friction stir welding between 5052 aluminum alloy and AZ31 magnesium alloy”, Transactions of Nonferrous Metals Society of China, 20: 619−623, (2010)
36. [36] Cao X. and Jahazi M., “Friction stir welding of dissimilar AA 2024-T3 to AZ31B-H24 alloys”, Materials Science Forum, 638-642: 3661-3666, (2010)
37. [37] Morishige T., Kawaguchi A., Tsujikawa M., Hino M., Hirata T. and Higashi K., “Dissimilar welding of Al and Mg alloys by FSW”, Materials Transactions, 49(5): 1129-1131, (2008)