Evaluation of Microstructure and Mechanical Properties of Friction Stir Lap Welded 6061 Aluminium Alloy at various welding speeds

Subject Areas :

فرهاد غروی ¹ , ایمان ابراهیم زاده ² , علی سهیلی ³

1 - استاد یار
2 - استاد یار
3 - مربی

Received: 2015-11-21 Accepted : 2016-09-13 Published : 2016-08-22

Keywords: Mechanical Properties, Friction Stir Welding, Lap joint, 6061 aluminum alloy, Welding Speed,

Abstract :

In this research the AA 6061-T6 aluminium alloy plates were welded by friction stir lap welding method. The effect of welding speeds on micro- and macro-structures and mechanical properties was investigated. The welding process was conducted by welding speed in the range 20-60 mm/min at constant rotation speed of 1000 rpm. The results showed that with increasing of welding speed, tensile shear strength and joint efficiency were increased from about 126 to 132 MPa and from about 40.6 to 42.5 (%), respectively. Although average micro-hardness of the weld nugget zone (WNZ) rather than the heat affected zone (HAZ) were increase with increasing welding speed, the average grain size in the WNZ and in the HAZ was decreased from about 43 to 32 µm and from about 99 to 87 µm, respectively. Due to increasing welding speed, the EPT with an increase in welding speed the hooking and thinning defects were gradually restricted from the WNZ to the WNZ/TMAZ interface. The fracture mode within the highest tensile shear strength joints was denoted as plate separation along the hook throughout the stir zone.

References:

[1]     W. M. Thomas, “Friction stir welding”, international patent application PCT/GB92, Patent application GB9125978.8, Vol. 6, 1991.

 

[2]     C.Y. Lee, W. B. Lee, J. W. Kim, D. H. Choi, Y. M. Yeon & S. B Jung, “Lap joint properties of FSWed dissimilar formed 5052Al and 6061Al alloys with different thickness”, Journal of Materials Science, Vol.43, pp. 3296-32304, 2008.

 

[3]     H. B. Chen, K. Yan, T. Lin, S. B. Chen, C. Y. Jiang & Y. Zhao, “The investigation of typical welding defects for 5456 aluminium alloy friction stir welds”, Materials Science and Engineering, Vol. 433A, pp. 64-69, 2006.

 

[4]     R. S. Mishra & Z. Y. Ma, “Friction stir welding and processing”, Materials Science and Engineering, Vol. 50R, pp. 1-78, 2005.

 

[5]     L. Dubourg, A. Merati & M. Jahazi, “Process optimization and mechanical properties of friction stir lap welds of 7075-T6 stringers on the 2024-T3 skin”, Materials and Design, Vol. 31, pp. 3324-3330, 2010.

 

[6]     M. W. Mahoney, C. G. Rhodes, J. G. Flintoff, R. A. Spurling & W. H. Bingel, “Properties of friction stir welded 7075-T651 aluminium”, Metallurgical and Materials Transaction, Vol. 29A, pp. 955-964, 1998.

 

[7]     G. M. D. Cantin, S. A. David, W. M. Thomas, E. Lara-Curzio & S. S. Babu, “Friction skew-stir welding of lap joints in 5083-O aluminium”, Science Technology Welding and Joining, Vol. 10, pp. 268-280, 2005.

 

[8]     L. Cederqvist & A. P. Reynolds, “Factors affected the properties of friction stir welded aluminium lap joints”, Welding Journal (Res. Supplement), Vol. 80, pp. 281-287, 2001.

 

[9]     M. Ericsson, L. Z. Jin & R. Sandstrom, “Fatigue properties of friction stir overlap welds” International Journal of Fatigue, Vol. 29, pp. 57-68, 2007.

 

[10] S. R. Ren, Z. Y. Ma & L. Q. Chen, “Effect of welding parameters on tensile properties and fracture behavior of friction stir welded Al-Mg-Si alloy”, Scripta Materialia, Vol. 56, pp. 69-72, 2007.

 

[11] X. Cao & M. Jahazi, “Effect of tool rotational speed and probe length on lap joint quality of friction stir welded magnesium alloy” Materials and Design, Vol. 32, pp. 1-11, 2011.

 

[12] S. Yazdanian & Z. W. Chen, “Effect of friction stir lap welding conditions on joint strength of aluminium alloy 6060”, IOP Conf. Series: Materials science and Engineering 4, Vol. 012021, 2009.

 

[13] S. Golezani, M. Esmaily & N. Mortazavi, “A Study on the Sub-Structure and Mechanical Properties of Friction Stir Processed AA 6061-T6 Joints with Ultra-Fine Grained Structure”, Journal of Advanced Materials and Processing, Vol. 2, No. 1, pp. 33-46, 2014.

 

[14]    ح. آقاجانی درازکلا، م. الیاسی و م. حسین زاده، " بررسی شکل گیری عیوب و لایه های بین فلزی در جوشکاری اصطکاکی اغتشاشی آلومینیم AA1100 به فولادA441 AISI"، فصلنامه علمی پژوهشی فرآیند های نوین در مهندسی مواد، سال نهم، شماره سوم، پاییز 1394.

 

[15]    ک. امینی، ف غروی، ا چمی ، م امیرخانی و ح قاسمی، "بررسی رفتار خوردگی مقطع جوشکاری شده آلیاژ آلومینیوم 5086 به روش جوشکاری اصطکاکی اغتشاشی"، فصلنامه علمی پژوهشی فرآیند های نوین در مهندسی مواد، سال هشتم، شماره چهارم، زمستان 1393.

 

[16] P. Pourahmad, M. Abbasi1 & H. A. Mehrabi, “Bimetal Friction Stir Welding of Aluminum to Magnesium”, Journal of Advanced Materials and Processing, Vol. 1, No. 1, pp. 27-38, 2013.

 

[17] C. Bitondo, U. Prisco, A. Squillace, G. Giorleo, P. Buonadonna, G. Dionoro & G. Campanile, “Friction stir welding of AA2198-T3 butt joints for aeronautical application”, International Journal of Materials Forming, Vol. 3, pp. 1079-1082, 2010.

 

[18] H. Aydin, M. Tutar, A. Durmus, A. Baryram & T. Sayaca, “Effect of welding parameters on tensile properties and fatigue behavior of friction stir welded 2014-T6 aluminium alloy”, Transaction Indian Institute of Metals, Vol. 65, pp. 21-30, 2012.

 

[19] S. Lim, S. A. Kim, C. Lee & S. U. Kim, “Tensile behaviour of friction stir welded Al 60601-T651”, Metallurgical and Materials Transaction, Vol. 35A, pp. 2829-2835, 2004.

 

[20] S. A. Khodir, T. Shibayanagi & M. Naka, “Microstructure and mechanical properties of friction stir welded AA2024-T3 aluminium alloy”, Materials Transactions, Vol. 47, pp. 185-193, 2006.

 

[21] G. D’Urso & C. Giardini, “The influences of process parameters and tool geometry on mechanical properties of friction stir welded aluminium lap joints”, International Journal of Materials Forming, Vol. 3, pp. 1011-1014, 2010.

 

[22] C. Sharma, D. K. Dwivedi & P. Kumar, “Effect of welding parameters on microstructure and mechanical properties of friction stir welded joints of AA7039 aluminium alloy”, Materials and Design, Vol. 36, pp. 379-390, 2012.

 

[23] Haydarzadeh, H. Khodaverdizaden, A. Mahmoudi & E. Nazari, “Tensile behavior of friction stir welded AA6061-T4 aluminium alloy joints”, Materials and Design, Vol. 37, pp. 166-173, 2012.

 

[24] G. Buffa, G. Campanile, L. Fratini & A. Prisco, “Friction stir welding of lap joints: influence of process parameters on the metallurgical and mechanical properties”, Materials Science and Engineering, Vol. 519A, pp. 19-26, 2009.

 

[25] X. Xu, X. Yang, G. Zhou & J. Tong, “Microstructures and fatigue properties of friction stir lap welds in aluminium alloy AA6061-T6”, Materials and Design, Vol. 35, pp. 175-183, 2012.

 

[26] S. Yazdanian, Z. W. Chen & G. Littlefair, “Effect of friction stir lap welding parameters on weld features on advancing side and fracture strength of AA6060-T5 welds”, Journal of  Materials Science, Vol. 47, pp. 1251-1261, 2012.

 

[27] American Welding Society, AWS D17.3/ D13.3M, “Specification for Friction Stir Welding of Aluminium Alloys for Aerospace Applications”, American national standard, 2010.

 

[28] “Standard Test Method for Macro etching Metals and Alloys”, ASTM Standard, E340, 1999.

 

[29] “Standard Test Method for Micro etching Metals and Alloys”, ASTM Standard, E407, 2007.

 

[30] “Standard Test Methods for Determining Average Grain Size”, ASTM Standard, E112, 2013.

 

[31] “Standard Test Method for Knoop and Vickers Hardness of Materials”, ASTM Standard, E384, 2011.

 

[32] Q. Yang, X. Li, K. Chen & Y. J. Shi, “Effect of tool geometry and process condition on static strength of magnesium friction stir lap linear weld”, Materials Science and Engineering, Vol. 528A, pp. 2463-2478, 2011.

 

[33] S. Babu, G. D. Janaki Ram, P. V. Venkitakrishnan, G. Madhusudhan Reddy & K. Prasad Rao, “Microstructure and Mechanical Properties of Friction Stir Lap Welded Aluminum Alloy AA2014”, Journal of Materials Science and Technology, Vol. 28, pp. 414-426, 2012.

 

[34] R, Nandan, T, Debroy & H. K. Bhadeshia, “Recent advances in friction stir welding-process, weldment structure and properties”, Progress in Materials Science, Vol. 53, pp. 980-1023, 2008.

 

[35] L. Liu, H. Nakayama, S. J. Fukumoto, A. Yamamoto & H. Tsubakino, “Microscopic Observations of Friction Stir Welded 6061 Aluminium Alloy”, Materials Transactions, Vol. 45, pp. 288-291, 2004.

 

[36] Z. Y. Ma, “Friction Stir Processing Technology: A Review”, Metallurgical and Materials Transaction, Vol. 39A, pp. 642-658, 2008.

 

[37] S. Rajakumar, C. Muralidharan & V. Balasubramaian, “Statistical analysis to predict grain size and hardness of the weld nugget of friction stir welded AA6061-T6 aluminium alloy joints”, International Journal of  Advanced Manufacturing Technology, Vol. 57, pp. 151-165, 2011.

 

[38] S. Rajakumar, C. Muralidharan & V. Balasubramanian, “Predicting Tensile Strength, Hardness and Corrosion Rate of Friction Stir Welded AA6061-T6 Aluminium Alloy Joints”, Materials and Design, Vol. 32, pp. 2878-2890, 2011.

 

[39] R. Rai, A. De, H. K. D. H. Bhadeshia & T. DebRoy, “Review: friction stir welding tools”, Science Technology of Welding and Joining, Vol. 16, pp. 325-342, 2011.

 

[40] W. Xu, J. Liu, G. Luan & C. Dong, “Temperature evolution, microstructure and mechanical properties of friction stir welded thick 2219-O aluminium alloy joints”, Materials and Design, Vol. 30, pp. 1886-1893, 2009.

 

[41] Zadpoor, J. Sinke & R. Benedictus, “Fracture mechanism of aluminium friction stir welded blanks”, International Journal of Materials Forming, Vol. 2, pp. 319–322, 2009.