Thermo-Mechanical Treated High Strength AA-7xxx Aluminium Alloy by Cold and Cryo-Rolling Study their Mechanical Properties Corrosion and Microstructure Correlation

Abstract:

Thermo-mechanical treatment, in particular, cryo-rolling is a unique technique to produce super high strength AA-7xxx aluminium alloys with ultra-fine grained structure. In order to conduct the rolling at room temperature and cryo-temperature (liquid N₂ (-190°C)), the AA-7xxx alloy ingot was rolled from 6mm to 1mm with 85% reduction in thickness. Optical microscopy, XRD, electron microscopy, hardness and tensile testing were conducted on the rolled alloy for understanding the phase changes and evaluating the mechanical properties. The alloy rolled at liquid nitrogen (LN₂) exhibits very high strength with reasonable ductility. Corrosion behaviour of AA-7xxx series aluminium alloy various conditions in NaCl (3.5%) solution were investigated. Cold rolled and cryo rolled alloy exhibits better corrosion resistance than that of cast.

• Periodical: Materials Science Forum (Volume 969)
• Pages: 62-67
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.969.62
• Online since: August 2019
• Authors: Y. Phaneendra, I.N. Niranjan Kumar, V.V. Ravi Kumar
• Keywords: AA-7xxx Alloy, Cold Rolling, Cryo Rolling, Mechanical Properties, Micro Structure Correlation, TEM Analysis

References

[1] Valiev, R.Z., Islamgaliev, R.K., Alexandrov, I.V., (2000). Bulk nanostructured materials from severe plastic deformation. Materials Science. 45, 103-109.

DOI: 10.1016/s0079-6425(99)00007-9

[2] Huang, Y., Prangnell, P.B., (2007). Continuous frictional angular extrusion and its application in the production of ultrafine-grained sheet. Scripta Material. 56, 333-336.

DOI: 10.1016/j.scriptamat.2006.11.011

[3] Alipour, M., Aghdam, B.G., Ebrahimi Rahnoma, H., Emamya, M., (2013). Investigation of the effect of Al–5Ti–1B grain refiner on dry sliding wear behaviour of an Al–Zn–Mg–Cu alloy formed by strain-induced melt activation process. Materials and Design. 46, 766-775.

DOI: 10.1016/j.matdes.2012.10.058

[4] Abolhasani, A., Zarei-Hanzaki, A., Abedi, H.R., Rokni, M.R., (2012). The room temperature mechanical properties of hot rolled 7075 alloy. Materials and Design. 34, 631-636.

DOI: 10.1016/j.matdes.2011.05.019

[5] Lang, Y., Hua, C., Cai, Y. Zhang, J., (2012). Effect of strain modified particles on the formation of fined grains and the properties of AA7050 alloy. Materials and Design. 39, 220-225.

DOI: 10.1016/j.matdes.2012.02.005

[6] Ramesh Kumar, S., Kondaiah, G., Venkatachalam, P., Ravisankar, B., (2010). Stress corrosion cracking of Al7075 alloy processed by equal channel angular pressing. International Journal of Engineering Science and Technology. 12, 53-61.

[7] Wang, Y., Chen, M., Zhou, F., Ma, E.,(2002). High tensile ductility in a nanostructured metal. Nature. 419, 912-915.

DOI: 10.1038/nature01133

[8] Rangaraju, N., Raghuram, T., Krishna, B.V., Rao, K.P., Venugopal, P., (2005). Effect of cryorolling and annealing on microstructure and properties of commercially pure aluminum. Materials Science & Engineering A, 398, 246-251.

DOI: 10.1016/j.msea.2005.03.026

[9] Lee, T.R, Chang, C.P., Kao, P.W., (2005). The tensile behaviour and deformation microstructure of cryorolled and annealed pure nickel. Materials Science & Engineering A. 408, 131-135.

DOI: 10.1016/j.msea.2005.07.045

[10] Lee, Y.B, Shin, D.H., Park, K.T., Nam, W.J., (2004). Effect of annealing temperature on microstructures and mechanical properties of a 5083 Al alloy deformed at cryogenic temperature. Scripta Material. 51, 355-359.

DOI: 10.1016/j.scriptamat.2004.02.037

[11] Nageswara rao, P., Jayaganthan, R., (2012). Effects of warm rolling and ageing after cryogenic rolling on mechanical properties and microstructure of Al 6061 alloy. Materials and Design. 39, 226-233.

DOI: 10.1016/j.matdes.2012.02.010

[12] Sanmugamsundram, T., Murthy, B.S., Subramanya sarma, V., (2006). Development of ultrafhine grained high strength Al-Cu alloy by cryorolling. Scripta Materialia. 54, 2013-2017.

DOI: 10.1016/j.scriptamat.2006.03.012

[13] Panigrahi, S., Jayaganthan, R., (2011). Effect of ageing on microstructure and mechanical properties of bulk, cryorolled, and room temperature rolled Al 7075 alloy. Journal of Alloys and Compounds. 509, 9609-9616.

DOI: 10.1016/j.jallcom.2011.07.028

[14] Jayaganthan, R., Brokmeier, H.G., Bernd, S., Panigrahi, S.K., (2010). Microstructure and texture evolution in cryorolled Al 7075 alloy. Journal of Alloys and Compounds. 496, 183-188.

DOI: 10.1016/j.jallcom.2010.02.111

[15] Panigrahi, S., Jayaganthan, R., (2011). Development of ultrafine grained high strength age hardenable Al 7075 alloy by cryorolling. Materials and Design. 32, 3150-3160.

DOI: 10.1016/j.matdes.2011.02.051

[16] Das, P., Jayaganthan, R., Singh, I.V., (2011). Tensile and impact-toughness behaviour of cryorolled Al 7075 alloy. Materials and Design. 32, 1298-1305.

DOI: 10.1016/j.matdes.2010.09.026

[17] Wua Y.L, U.F.H. Froesa, A.Alaverza, C.G. Lib and J.Liuc (1997). Microstructure of properties of a new super-high strength Al-Zn-Mg-Cu alloy-C912. Materials & Design, 18(46): 211-215.

DOI: 10.1016/s0261-3069(97)00084-8