Corrosion behavior of dissimilar copper/brass joints welded by friction stir lap welding in alkaline solution

Abstract

This study was done to evaluate the nugget zone (NZ) corrosion behavior of dissimilar copper/brass joints welded by friction stir lap welding (FSLW) in a solution of 0.015 mol/L borax (pH 9.3). To this end, dissimilar copper/ brass plates were welded with two dissimilar heat inputs (low and high) during the welding procedure. The high and low heat inputs were conducted with 710 r/min, 16 mm/min and 450 r/min, 25 mm/min, respectively. Using open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS) and Tafel polarization tests, the electrochemical behavior of the specimens in borate buffer solution was assessed. With the help of scanning electron microscope (SEM), the morphology of welded specimen surfaces was examined after immersion in the test solution. According to the results, the NZ grain size and resistance improvement reduced due to the nugget zone corrosion with a decreased heat input. The results obtained from Tafel polarization and EIS indicated the improved corrosion behavior of the welded specimen NZ with a decrease in the heat input during the welding process unlike the copper and brass metals. Furthermore, an increased heat input during the welding process shows a reduction in the conditions for forming the passive films with higher protection behavior.

Keywords

friction stir welding / copper / brass alloy / corrosion behavior / alkaline solution / dissimilar joint

References

[1] KundigK J A, CowieJ GCopper and copper alloys [M]// MUPYER K. Mechanical Engineers' Handbook, 2006, New Jersey, Wiley Interscience: 117220

[2] ZhouL, HuangY X, DongS, ZhouW L, FengJ C, HeW X. Effect of rotation speed on the microstructure and mechanical properties of dissimilar friction stir-welded copper/brass metals [J]. International Journal of Advanced Manufacturing Technology, 2016, 84(5–8): 1335-1343

[3] ErdemM. Study the structure and mechanical properties of copper-brass plates joined by friction stir welding [J]. International Journal of Advanced Manufacturing Technology, 2015, 76: 1583-1592

[4] ThomasW M, NicholasE D, TemplesmithP, DawesC J, NeedhamJ C, MurchM GFriction stir welding: International Patent Application, 1991

[5] RadovanovićM B, Milić SM, SimonovićA T, PetrovićMB, AntonijevićM. The impact of purine on brass behavior in neutral and alkaline sulphate solutions [J]. International Journal of Electrochemistry Society, 2012, 7: 11796-11810

[6] MeranC. The joint properties of brass plates by friction stir welding [J]. Materials & Design, 2006, 27: 719-726

[7] AlfantaziA M, AhmedT M, TromansD. The copper alloys corrosion behavior of in chloride media [J]. Materials & Design, 2009, 30: 2425-2430

[8] ProcacciniR, VázquezM, CeréS. Copper and brass aged at open circuit potential in slightly alkaline solutions [J]. Electrochimica Acta, 2009, 54: 7324-7329

[9] ProcacciniR, VazquezM, SchreinerW H, CeréS. The study of films' surface formed on copper and brass at open circuit potential [J]. Applied Surface Science, 2013, 268: 171-178

[10] BitonM, SalitraG, IlzycerD, AurbachD, MishkovP. The electrochemical behavior and passivation of copper and brass (Cu70/Zn30) electrodes in the concentrated aqueous KOH solutions [J]. Journal of Electrochimica Society, 2006, 153: B555-B565

[11] KunzeJ, MauriceV, StrehblowH, KleinL H, MarcusP. In situ STM study of the duplex passive films formed on Cu (111) and Cu (001) in 0.1 M NaOPH [J]. Corrosion Science, 2004, 46: 245-264

[12] MikicT K, MilosevI, PihlarB. Passivity and corrosion of Cu-XZn (X=10-40 wt.%) alloys in borate buffer containing chloride ions [J]. Journal of Applied Electrochemistry, 2005, 35: 975-984

[13] Fattah-AlhosseiniA, KeshavarzM K, TaheriA H. Friction stir welding effects on electrochemical behavior of pure copper [J]. Transactions of Indian Institute of Metals., 2016, 69(7): 1423-1434

[14] FengY, TanK L, SiowK S, TeoW K, HsiehA K. The corrosion mechanisms and products of copper in aqueous solutions at different pH values [J]. Corrosion, 1997, 53(5): 389-398

[15] MilosevI, MikićT K, GaberščekM. The effect of Cu-rich sub-layer on the increased corrosion resistance rate of Cu-xZn alloys in chloride solution containing borate buffer [J]. Electrochimica Acta, 2006, 52: 415-426

[16] KilinccekerG, ErbilM. The effects of phosphate ions on the electrochemical behavior of brass in sulphate solutions [J]. Materials Chemistry & Physics, 2010, 119: 30-39

[17] GharaviF, FadaeifardF, MatoriKA, YunusR, OthmanN K. Mechanical and structural evaluation of friction stir welded 6061 aluminum alloy lap joints at different welding speeds [J]. Kovove Materially, 2016, 54: 1-11

[18] AminiK, GharaviF. Influence of welding speed on corrosion behavior of friction stir welded AA5086 aluminum alloy [J]. Journal of Central South University, 2016, 23: 1301-1311

[19] GharaviF, EbrahimzadehI, AminiK, DaryaP. Evaluation of the microstructure and mechanical properties of friction stir-welded copper/brass dissimilar joints [J]. Materials Research Express, 2018, 5(7): 076517

[20] TaoS, LiD Y. Tribological, mechanical and electrochemical properties of monocrystalline copper deposits produced by pulse electrodeposition [J]. Nanotechnology, 2006, 17: 65-78

[21] RalstonK D, BirbillisN. Effect of grain size on corrosion: A review [J]. Corrosion, 2010, 66(7): 075005

[22] BadawyW A A-, KharafiF M. The brass alloys corrosion behavior in aqueous solutions with different pHs [J]. Corrosion, 1999, 55268-274

[23] AntonijevicM, PetrovicM B, BogdanovicG D, RadovanovicM B, StamenkovicA T. The effects of pH and chloride ions on electrochemical behavior of brass in alkaline solution [J]. International Journal of Electrochemical Society, 2009, 4654-661

[24] SarlakH, AtapourM, EsmailzadehM. The corrosion behavior of friction stir welded lean duplex stainless steel [J]. Materials & Design, 2015, 66: 209-215

[25] Fattah-AlhosseiniA, ImantalabO. The accumulative roll bonding process effect on the electrochemical behavior of pure copper [J]. Journal of Alloys & Compounds, 2015, 632: 48-54

[26] ImantalabO, Fattah-AlhosseiniA. Electrochemical and passive behaviors of pure copper fabricated by accumulative roll bonding (ARB) process [J]. Journal of Materials Engineering and Performance, 2015, 24: 2579-2585