Effect of chloride ion concentration, spraying time and pH values on corrosion behavior of friction stir welded AZ61A magnesium alloy welds in salt fog environments

Yıl 2013, Cilt: 2 Sayı: 2, 147 - 167, 27.03.2016

A. Dhanapal S. Rajendra Boopathy V. Balasubramanian -

https://doi.org/10.12748/uujms.201324256

Öz

The present research devoted to the investigation of the corrosion behavior of AZ61A FSW welds in accelerated conditions, including the influence of salt fog environmental parameters such as chloride ion concentration, pH, and duration of exposure. Significant numbers of tests were carried out that make possible to create the regression model (empirical equation) of influence of selected environmental parameters on corrosion rate. The corrosion products were analyzed by SEM and XRD analysis. This research demonstrates the effect of chloride ion concentrations, spraying time and pH values on corrosion rate, and it show the corrosion activity decelerates with the increasing pH value and spraying time respectively. It was found that the increase in chloride ion concentration accelerates the corrosion of AZ61A weldments. The corrosion morphology was predominantly influenced by the distribution of β-phase (e.g. Mg17Al12 intermetallic).

Anahtar Kelimeler

Magnesium alloy, friction stir welding, salt fog tests, weight loss, corrosion rate

Kaynakça

• Zeng RC, Dietzel W, Zettler R and Chen J. Microstructure evolution and tensile properties of friction-stir-welded AM50 magnesium alloy. Transaction of Nonferrous Metal Society of China, 2008; 18: 76 – 80.
• Zeng RC, Dietzel W, Huang WJ, Kainer KU, Zettler R and Zhang J. Review of studies on corrosion of magnesium alloys. Transaction of Nonferrous Metal Society of China, 2006; 16: 763 – 771.
• Nagasawa T, Otsuka M, Yokota T and Ueki T. Structure and mechanical properties of friction stir weld joints of magnesium alloy AZ31. Magnesium Technology, 2000; TMS: 383 – 387.
• LeBozec N, Jönsson M and Thierry D. Atmospheric corrosion of magnesium alloys: Influence of temperature, relative humidity, and chloride deposition. Corrosion, 2004; 60: 356 – 362.
• Zhao MC, Liu M, Song G and Atrens A. Influence of pH and chloride ion concentration on the corrosion of Mg alloy ZE41. Corrosion Science, 2008; 50(11): 3168 – 3178.
• Hawke DL, Hillis JE, Pekguleryuz M and Nkatusugawa I, in: Avedesian MM, Baker H(Eds.). Magnesium and Magnesium Alloys. ASM International, Materials Park, 1999: 194 – 210.
• Abady MG, Hillal HN, El- Rabieee M and Badary AN. Effect of Al content on the corrosion behavior of Mg-Al alloys in aqueous solutions of different pH. Electrochemical Acta, 2010, 55: 6651 – 6658.
• Merins MC, Paradr A, Arrabal R and Morine S. Influence of chloride ion concentration and temperature on the corrosion of Mg-Al alloy in salt fog. Corrosion science, 2010, 52: 1696 – 1764.
• Song G, Atrens A, Wu X and Zhang B. Corrosion behavior of AZ21, AZ501, AZ91 in NaCl. Corrosion Science, 1998; 40: 1769 – 1791.
• Ambat R, Aung NN and Zhao W. Evaluation of microstructural effects of corrosion behavior of AZ91 D Mg alloy. Corrosion Science, 2000; 42: 1433 – 14
• Hara N, Kobayashi Y, Kagaya D and Akao N. Formation and breakdown of surface films on magnesium and its alloys in aqueous solutions. Corrosion Science, 2007; 49: 166 – 175.
• Schumtz P, Guiaumin V, Lilard RS, Lilard JA and Frankela GS. Influence of dichromate ions on corrosion process on pure magnesium. Journal of electrochemical society, 2003; 150: B99 – B110.
• Zeng RC, Chen J, Dietzel W, Zettler R, F. Dos Santos J, Nascimento ML and Kainer KU. Corrosion of friction stir welded magnesium alloy AM50. Corrosion Science, 2009; 51: 1738 – 1746.
• Song G and Atrens A. Understanding magnesium corrosion – a framework for improved alloy performance. Advanced Engineering Materials. 2003; 5: 837 – 8
• Altun H and Sen S. Studies on the influence of chloride ion concentration and pH on the corrosion behavior of AZ63 magnesium alloy. Materials & Design, 2004; 25: 637 – 643.
• Song Y, Shan D, Chen R and Han EH. Effect of second phases on the corrosion behavior of wrought Mg-Zn-Y-Zr alloy. Corrosion Science, 2010: 52: 1830 – 18
• Dhanapal A, Boopathy SR and Balasubramanian V. Developing an empirical relationship to predict the corrosion rate of friction stir welded AZ61A magnesium alloy under salt fog environments. International Journal of Materials and Design, 2011; 32: 5066 – 5072.
• Dhanapal A, Boopathy SR and Balasubramanian V. Influence of pH values, chloride ion concentration and immersion time on corrosion rate of friction stir welded AZ61A magnesium alloy weldments. International Journal of Alloys and compounds, 2012: 523: 49 – 60.
• Neil WC, Forsyth M, Howlettt PC, Hutchison CR and Hinton BRW. Corrosion of magnesium alloy ZE41 – The role of microstructural features. Corrosion Science, 2009; 51: 387 – 394.
• Lafront AM, Zhang W, Jin S, Tremblay R, Dube D and Ghali E. Pitting Corrosion of AZ91D and AJ62x magnesium alloys in alkaline chloride medium using electrochemical techniques. Electrochimica Acta, 2005; 51: 489 – 501. Zhao MC, Liu M, Song GL and Atrens A. Influence of pH and chloride ion concentration on the corrosion of Mg alloy ZE41. Corrosion Science, 2008; 50: 3168 – 3178.
• Gao L, Zhang C, Zhang M, Huang X and Sheng N. The corrosion of a novel Mg11Li-3Al-0.5RE alloy in alkaline NaCl solution. Journal of alloy compounds, 2007: 285 – 289.
• Xin R, Li B, Li L and Liu Q. Influence of texture on corrosion rate of AZ31 Mg alloy in 5wt% NaCl. Materials and Design, 2011: 4548 – 4552.
• Balasubraminan P, Zetler R, Blawert C and Dietzel W. A study on the effect of plasma electrolytic oxidation on the stress corrosion cracking behavior of wrought AZ61 Mg alloy and its friction stir welding. Material and characteristics, 2009, 60: 289 – 389.