Influence of welding speed on corrosion behaviour of friction stir welded AA5086 aluminium alloy

Abstract

The plates of AA5086 aluminium alloy were joined together by friction stir welding at a fixed rotation speed of 1000 r/min various welding speeds ranging from 63 to 100 mm/min. Corrosion behavior of the parent alloy (PA), the heat affected zone (HAZ), and the weld nugget zone (WNZ) of the joints were studied in 3.5% (mass fraction) aerated aqueous NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The corrosion susceptibility of the weldments increases when the welding speed increases to 63 and 100 mm/min. However, the value of corrosion rate in the weldments is lower than that in the PA. Additionally, the corrosion current density increases with increasing the welding speed in the HAZ and the WNZ. On the contrary, the corrosion potential in the WNZ appears more positive than in the HAZ with decreasing the welding speed. The WNZ exhibits higher resistance compared to the HAZ and the PA as the welding speed decreases. The results obtained from the EIS measurements suggest that the weld regions have higher corrosion resistance than the parent alloy. With increasing the welding speed, the distribution and extent of the corroded areas in the WNZ region are lower than those of the HAZ region. In the HAZ region, in addition to the pits in the corroded area, some cracks can be seen around the corroded areas, which confirms that intergranular corrosion is formed in this area. The alkaline localized corrosion and the pitting corrosion are the main corrosion mechanisms in the corroded areas within the weld regions. Crystallographic pits are observed within the weld regions.

Keywords

friction stir welding / aluminum alloy / corrosion properties / welding speed

References

[1] ThomasW M, NicholasE D, NeedhamJ C, MurchM G, Temple-SmithP, DawesC J. Friction stir welding and processing [P]. International patent application, 1991

[2] TejonadhaB K, KranthiK P, MuthukumaranS. Mechanical, metallurgical characteristics and corrosion properties of friction stir welded AA6061-T6 using commercial pure aluminium as a filler plate [J]. Procedia Materials Science, 2014, 6: 648-655

[3] DawesC J, ThomasW M. Friction stir process welds aluminium alloys: The process produces low-distortion, high-quality, low-cost welds on aluminium [J]. Welding Journal, 1996, 75: 41-45

[4] D’UrsoG, GiardiniC. The influences of process parameters and tool geometry on mechanical properties of friction stir welded aluminum lap joints [J]. International Journal of Material Forming, 2010, 3: 1011-1014

[5] CantinG M D, DavidS A, ThomasW M, Lara-CurzioE, BabuS S. Friction skew-stir welding of lap joints in 5083-O aluminium [J]. Science and Technology of Welding and Joining, 2005, 10: 268-281

[6] KulekciM K, SikA, KaluçE. Effects of tool rotation and pin diameter on fatigue properties of friction stir welded lap joints [J]. International Journal of Advanced Manufacturing Technology, 2008, 36: 877-882

[7] MishraR S, MaZ Y. Friction stir welding and processing [J]. Materials Science and Engineering R, 2005, 50: 1-78

[8] FahimpourV, SadrnezhaadS K, KarimzadehF. Corrosion behavior of aluminum 6061 alloy joined by friction stir welding and gas tungsten arc welding methods [J]. Materials and Design, 2012, 39: 329-333

[9] BagheriH M, GholamiS S, YaghoubinezhadY, MohammadiR M. The optimum combination of tool rotation rate and traveling speed for obtaining the preferable corrosion behavior and mechanical properties of friction stir welded AA5052 aluminum alloy [J]. Materials and Design, 2013, 50: 620-634

[10] DongP, SunD, WangB, ZhangY, LiH. Microstructure, microhardness and corrosion susceptibility of friction stir welded AlMgSiCu alloy [J]. Materials and Design, 2014, 54: 760-765

[11] DongP, SunD, LiH, GongW, LiuJ. Effects of welding speed on the microstructure and hardness in friction stir welding joints of 6005A-T6 aluminum alloy [J]. Materials and Design, 2013, 45: 524-531

[12] XuW, LiuJ, ZhuH. Pitting corrosion of friction stir welded aluminum alloy thick plate in alkaline chloride solution [J]. Electrochimica Acta, 2010, 55: 2918-2923

[13] ProtonV, AlexisJ, AndrieuE, DelfosseJ, LafontM C, BlancC. Characterization and understanding of the corrosion behavior of the nugget in a 2050 aluminium alloy friction stir welding joint [J]. Corrosion Science, 2013, 73: 130-142

[14] ProtonV, AlexisJ, AndrieuE, BlancC, DelfosseJ. Influence of post welding heat treatment on the corrosion behavior of a 2050-T3 aluminum–copper–lithium alloy friction stir welding joint [J]. Journal of Electrochemistry Society, 2011, 158: 139-47

[15] PadovaniC, DavenportA J, ConnollyB J, WilliamsS W, SiggsE, GrosoA. Corrosion protection of AA2024-T351 friction stir welds by laser surface melting with Excimer laser [J]. Corrosion Engineering Science and Technology, 2012, 47: 188-202

[16] BousquetE, Poulon-QuintinA, PuiggaliM, DevosO, TouzetM. Relationship between microstructure, microhardness and corrosion sensitivity of an AA 2024-T3 friction stir welded joint [J]. Corrosion Science, 2011, 53: 3026-34

[17] VijayaK P, MadhusudhanR G, SrinivasaR K. Microstructure and pitting corrosion of armor grade AA7075 aluminum alloy friction stir weld nugget zone—Effect of post weld heat treatment and addition of boron carbide [J]. Defence Technology, 2015, 11: 166-173

[18] LiW Y, JiangR R, HuangC J, ZhangZ H, FengY. Effect of cold sprayed Al coating on mechanical property and corrosion behavior of friction stir welded AA2024-T351 joint [J]. Materials and Design, 2015, 65: 757-761

[19] KangJ, FuR D, LuanG H, DongC L, HeM. In-situ investigation on the pitting corrosion behavior of friction stir welded joint of AA2024-T3 aluminium alloy [J]. Corrosion Science, 2010, 52: 620-626

[20] WangQ, ZhaoY, YanK, LuS. Corrosion behavior of spray formed 7055 aluminum alloy joint welded by underwater friction stir welding [J]. Materials and Design, 2015, 68: 97-103

[21] FondaR W, PaoP S, JonesH N, FengC R, ConnollyB J, DavenportA J. Microstructure, mechanical properties, and corrosion of friction stir welded Al 5456 [J]. Materials Science and Engineering A, 2009, 519: 1-8

[22] ZucchiF, TrabanelliG, GrassiV. Pitting and stress corrosion cracking resistance of friction stir welded AA5083 [J]. Materials and Corrosion, 2001, 52: 853-859

[23] LeeCCorrosion testing of aluminium alloy friction stir welds- Literature review [R], 2003

[24] HaverW, MeesterB, GeurtenA, DefrancqJ. Project P2/00/02–Innovative joining of critical aluminium structures with the friction stir welding technique–CASSTIR [R]. Belgian Science Policy, 2010

[25] WadesonD A, ZhouX, ThompsonG E, SkeldonP, OosterkampL D, ScamansG. Corrosion behaviour of friction stir welded AA7108 T79 aluminium alloy [J]. Corrosion Science, 2006, 48: 887-97

[26] FrankelG, XiaZ. Localized corrosion and stress corrosion cracking resistance of friction stir welded aluminium alloy 5454 [J]. Corrosion, 1999, 55: 139-150

[27] CamG, GuclureS, CakanA, SerindangH T. Mechanical properties of friction stir butt welded Al-5086 plate [J]. Materials and Corrosion, 2009, 4: 638-642

[28] TabanE, KalucE. Comparison between microstructure characteristics and joint performance of 5086-H32 aluminium alloy welded by MIG, TIG and friction stir welding processes [J]. Kovove Material, 2005, 45: 241-248

[29] JamshidiA H, SerajzadehS, KokabiA H. Theoretical and experimental investigation into friction stir welding of AA 5086 [J]. International Journal of Advanced Manufacturing Technology, 2011, 52: 531-544

[30] AkbariM S A A, ShamabadiS H. Dissimilar friction stir welds in AA 5086-AA 2024: The effect of process parameters on microstructures and mechanical properties [J]. Advanced Materials Research, 2012, 445: 753-758

[31] PradeepS, ShamraS K, PancholiV. Microstructural and mechanical characterization of friction stir processed 5086 aluminum alloy [J]. Materials Science Forum, 2012, 710: 253-257

[32] G-59-973. Standard Test Method for Conducting Potentiodynamic Polarization Resistance Measurements [S]. ASTM, 2014.

[33] G-106-89. Standard Practice for Verification of Algorithm and Equipment for Electrochemical Impedance Measurements [S]. ASTM, 2010.

[34] SomasekharanA, MurrL. Microstructures in friction-stir welded dissimilar magnesium alloys and magnesium alloys to 6061-T6 aluminum alloy [J]. Materials Characterization, 2004, 52: 49-64

[35] EzuberH, El-HoudA, El-ShaweshF. A study on the corrosion behavior of aluminium alloy in seawater [J]. Materials and Design, 2008, 29: 801-805

[36] AballeA, BethencourtM, BotanaF J, CanoM J, MarcosM. Localized alkaline corrosion of alloy AA5083 in netural 3.5% NaCl Solution [J]. Corrosion Science, 2001, 43: 1657-1674

[37] AballeA, BethencourtM, BotanaF J, CanoM J, MarcosM. Influence of cathodic intermetallics distribution on the reproducibility of the electrochemical measurements on AA5083alloy in NaCl Solution [J]. Corrosion Science, 2003, 45: 161-180

[38] YasakauK A, ZheludkevichM L. Role of intermetallic phases in localized corrosion of AA5083 [J]. Electrochimica Acta, 2007, 52: 7651-7659

[39] ChoiD H, AhnB W, QuesnelD J, JungS B. Behavior of ß phase in AA5083 during friction stir welding [J]. Intermetallics, 2013, 35: 120-127

[40] AmbatR, DavenportA, ScamansG, AfsethA. Effect of iron-containing intermetallic particles on the corrosion behaviour of aluminium [J]. Corrosion Science, 2006, 48: 3455-3471

[41] ZhangD Q, LiJ, JooH G, LeeK Y. Corrosion properties of Nd:YAG laser-GMA hybrid welded AA6061 Al alloy and its microstructure [J]. Corrosion Science, 2009, 51: 1399-1404