Influence of Tool Offset Distance on Microstructure and Mechanical Properties of the Dissimilar AA2024–AA7075 Plates Joined by Friction Stir Welding

Subject Areas : advanced manufacturing technology

Hossain Soleimany ¹ , kamran amini ² , Farhad Gharavi ³

1 - Department of Mechanical Engineering, Khomeini-shar Branch, Islamic Azad University, Isfahan, Iran
2 - Centre for Advanced Engineering Research, Majlesi Branch, Islamic Azad University, Isfahan, Iran
3 - Department of Materials Engineering, Sirjan Branch, Islamic Azad University, Sirjan, Iran

Received: 2020-04-14 Accepted : 2020-08-08 Published : 2020-12-01

Keywords: Tool Offset, Mechanical Properties, Friction Stir Welding, Dissimilar joint,

Abstract :

In the present study, the effect of tool offset on microstructure and mechanical properties of dissimilar friction stir welding of Al2024 and Al7075 alloys were investigated. In this regard, base metals were welded by FSW under different tool offsetting conditions, 1.5 and 2 mm shifted into Al2024 and Al7075 alloys, respectively, in addition to constant rotation rates and traverse speeds named as 710 rpm and 28 mm/min respectively. The microstructure of different welding zones and fracture surface were investigated by an Optical Microscope (OM) and Scanning Electron Microscopy (SEM), respectively. The results showed that by tool offsetting from the weld center through Al2024, an onion-shaped area has been created and mixture happens completely. However, by tool off-setting towards Al7075, onion-shaped microstructure fails to be formed in the stirred area. From the results of the tensile test, it is presented that maximum tensile strength is obtained in samples with a tool offsetting into the Al7075. With 1.5 mm tool offsetting into Al2024, first, joint tensile strength increases by 22.2 % in comparison to non-offset condition, and then, with more tool offset as much as 2 mm, tensile strength decreases by 22.2 %. In addition, by tool offsetting towards Al7075 by 1.5 and 2 mm, joint tensile strength decreases by 4.5 and 28.5 %, respectively. It is also concluded that in the offset samples towards the 7075 alloy, the microhardness in the HAZ area decreased compared to the microhardness of the offsets samples towards the 2024 alloy. Finally, the best mechanical behavior and microstructural properties were obtained in the sample with the tool offset of about 1.5 mm towards the welded Al2024 base metal (70215 samples) alloy.

References:

[1]     Kissel, J. R., Ferry, R. L., Aluminum Structures, Fourth Edition, John Wiley and Sons Inc, United States of America, 1990, pp.10-13.

[2]     Davis, J. R, Aluminum and Aluminum Alloys, ASM International, 2001, pp. 351-416.

[3]     Martukanitz, R. P., Selection and Weldability of Aluminum Alloys, ASM Handbook, Welding, Brazing, and Soldering, ASM International Committee, Vol. 6, 1993, pp. 526-536.

[4]     Mathers, G., The Welding of Aluminium and Its Alloy, Woodhead Publishing Ltd and CRC Press LLC, England, 2002, pp. 2-167.

[5]     Madhusudhan Reddy, G., Gokhale, A. A., and Prasad Rao, K., Optimization of Pulse Frequency in Pulsed Current Gas Tungsten Arc Welding of Aluminum– Lithium, Journal of Materials Science Technology, Vol. 14, 1998, pp. 61–66,

[6]     Lakshminarayanan, A. K., Balasubramanian, V., and Elangovan, K., Effect of Welding Processes On Tensile Properties of AA6061 Aluminium Alloy Joints, International Journal of Advanced Manufacturing Technology, Vol. 40, 2009, pp. 286–296.

[7]     Saravanan, V., Banerjee, N., Amuthakkannan, R., and Rajakumar, S., Microstructural Evolution and Mechanical Properties of Friction Stir Welded Dissimilar AA2014-T6 and AA7075-T6 Aluminum Alloy Joints, Metallography and Microstructures Analysis, Vol. 4, 2015, pp.178–187.

[8]     Thomas, W., Lockyers, M., Kalee, S. A., and Staines, D. G., Friction Stir Welding- an Update On Recent Developments, from a Paper Presented at IMECH Stressed Components in Aluminum Alloys, A, 2003.

[9]     Vilaca, P., Thomas, W., Friction Stir Welding Technology, Verlag berlin Heidelberg, Vol. 10, 2011, pp. 1007-1056,

[10]  Crawford, R., A Mechanical Study of the Friction Welding Process, Ph.D. Dissertation Graduate School of Vanderbit University, Nashrrille, Tennessee, 2006.

[11]  Zhi-hong, F. U., Di-Qiu, H. E., and Hong, W., Friction Stir Welding of Aluminum Alloys, Wuhan University of Technology Material Science, Vol. 19, 2004, No. 1, pp. 61-64.

[12]  Baghdadi, A. H., Selamat, F. M., and Sajuri, Z., Effect of Tool Offsetting On Microstructure and Mechanical Properties Dissimilar Friction Stir Welded Mg-Al Alloys, Materials Science and Engineering, 2017, Vol. 238. 

[13]  Ramachandran, K. K., Murugan, N., and ShashiKumar, S., Effect of Tool Axis Offset and Geometry of Tool Pin Profile On the Characteristics of Friction Stir Welded Dissimilar Joints of Aluminum Alloy AA5052 and HSLA steel, Materials Science & Engineering A, Vol. 639, 2015, pp. 219–233.

[14]  Kumar Sahua, P., Pala, S., Palb, S. K., and Jain, R., Influence of Plate Position, Tool Offset and Tool Rotational Speed on Mechanical Properties and Microstructures of Dissimilar Al/Cu Friction Stir Welding Joints, Materials Processing Technology, Vol. 235, 2016, pp. 55-67.

[15]  Karimi, N., Nourouzi, S., Shakeri, M., Habibnia, M., and Dehghani, A., Effect of Tool Material and Offset On Friction Stir Welding of Al Alloy to Carbon Steel, Advanced Materials Research Vol. 445, 2012, pp. 747-752.

[16]  Miao, Y., Han, D., Yao, J., and Li, F., Effect of Laser Offsets On Joint Performance of Laser Penetration Brazing for Magnesium Alloy and Steel, Materials and Design, Vol. 31, 2010, pp. 3121–3126.

[17]  ASTM E8-00 Standard Test Methods for Tension Testing of Metallic Materials.

[18]  ASTM E92-82 Standard Test Method for Vickers Hardness of Metallic Materials.

[19]  Yan, X., Ma, H., Xiong, L., Tian, Z., Cao1, X., and Zhang, Y., Effect of Lateral Offset On Microstructure and Strength of Friction Stir Welded 2A14-T6 Aluminum Alloy, Advanced Manufacturing Technology, Vol. 97, 2018, pp. 3893–3902.

[20]  Cavaliere, P., Panella, F., Effect of Tool Position On the Fatigue Properties of Dissimilar 2024-7075 Sheets Joined by Friction Stir Welding, Materials Processing Technology, Vol. 206, 2008, pp. 249–255.

[21]  Bahemmat, P., Haghpanahi, M., Besharati Givi, M. K., and Seighalani, K. R., Study on Dissimilar Friction Stir Butt Welding of AA7075-O and AA2024-T4 Considering the Manufacturing Limitation, International Journal of Advanced Manufacturing Technology, Vol. 59, 2012, pp. 939–953.

[22]  Cavaliere, P., Nobile, R., and Panella, F., Mechanical and Microstructural Behavior of 2024–7075 Aluminum Alloy Sheets Joined by Friction Stir Welding, International Journal of Machine Tools Manufactures, Vol. 46, 2006, pp. 588–594.

[23]  Da Silva, A. A. M., Arruti, E., Janeiro, G., Aldanondo, E., Alvarez, P., and Echeverria, A., Material Flow and Mechanical Behavior of Dissimilar AA2024-T3 and AA7075-T6 Aluminium Alloys Friction Stir Welds, Materials and Design, Vol. 32, pp. 2021–2027, 2011.

[24]  Ahmed Khodir, S., Shibayanagi, T., Friction Stir Welding of Dissimilar AA2024 and AA7075 Aluminum Alloys, Materials Science Engineering B, Vol. 148, 2008, pp. 82–87.

[25]  Muthua, M. F. X., Jayabalan, V., Tool Travel Speed Effects On the Microstructure of Friction Stir Welded Aluminum–Copper Joints, Materials Processing Technology, Vol. 217, 2015, pp. 105–113.

[26]  Song, Y., Yang, X., Cui, L., Hou, X., Shen, Zh., and Xu, Y., Defect Features and Mechanical Properties of Friction Stir Lap Welded Dissimilar AA2024–AA7075 Aluminum Alloy Sheets, Materials and Design, Vol. 55, 2014, pp. 9–18.

[27]  Cantin, G. M. D., David, S. A., Thomas, W. M., Curzio, E., and Babu, S. S., Friction Skew-Stir Welding of Lap Joints in 5083–O Aluminium, Science and Technology of Welding and Joining, Vol. 10, No. 3, 2005, pp. 268-280.