Microstructure and texture evolution during accumulative roll bonding of aluminium alloys AA2219/AA5086 composite laminates Shibayan Roy • B. R. Nataraj • Satyam Suwas • S. Kumar • K. Chattopadhyay Received: 14 February 2012 / Accepted: 8 May 2012 / Published online: 26 May 2012 Ó Springer Science+Business Media, LLC 2012 Abstract Accumulative roll bonding of two aluminium alloys, AA2219 and AA5086 was carried out up to 8 passes. During the course of ARB, the deformation inhomogeneity between the two alloy layers results in interfacial instability after the 4th pass, necking of the AA5086 layers after the 6th pass and fracture along the necked regions after the 7th and 8th pass. The EBSD analysis shows deformation bands along the interfaces after 8 passes of ARB. The ARB- processed materials predominantly show characteristic deformation texture components. The weak texture after the 2nd pass results from the combination of a weakly-textured starting AA2219 layer and a strongly-textured starting AA5086 layer. A strong deformation texture forms due to the high imposed strain after a higher number of ARB pas- ses. Subgrain formation and related shear banding induces copper/S components in the case of the small elongated grains, while planar slip leads to the formation of brass component in the large elongated grains. Introduction The stringent criteria of superior strength with sufficient ductility for aerospace and automotive materials has provided the required thrust for the development of novel microstruc- tures and processing techniques in the recent past [1]. Out of various strengthening mechanisms, grain size refinement has attracted considerable interest due to the simultaneous improvement of strength and ductility. Fabricating materials with small grain sizes, either in the ultrafine (UFG, grain size 0.1–1 lm) or nano-crystalline regime (grain size \ 100 nm) leads to severe plastic deformation (SPD) based approaches to generate fine grain sizes in bulk materials [2]. Significant microstructural refinement is achieved through different SPD processes, e.g. equal channel angular pressing, high pressure torsion, multi-axial forging, cyclic extrusion compression etc. [3–9]. Accumulative roll bonding (ARB) is one such SPD process which has been found advantageous since it does not require specialized forming facilities with a large load capacity. Aluminium and its alloys are important in the aerospace and automotive industries due to their high specific prop- erties [1]. The microstructure and texture evolution in ARB- processed pure aluminium (1xxx) [10] as well as 2xxx [11], 3xxx [12], 5xxx [13], 6xxx [14], 7xxx [15], and 8xxx [16] series aluminium alloys has been extensively studied. More specifically, the ARB of Al–Mn alloy [17, 18], Al–Si alloy [19], Al–Fe–Si alloy [20], Al–Sc alloy [21] etc. has been reported in literature. A common variation in ARB pro- cessing is the fabrication of laminated composites by stacking dissimilar metals in alternate layers. Various metals have been tried in combination with aluminium alloys in these laminates such as Al/Cu, Al/Mg, Al/Ni, Al/Ti, Al/Steel etc. [22–27]. These laminated materials more commonly behave in a composite manner and therefore, substantial property improvement is expected in service. More recently, an improved approach of producing lami- nated composites via ARB has been frequently reported by stacking with two different aluminium alloys in alternate layers. A notable advantage of this methodology is better interfacial bonding while maintaining cumulative improve- ment in various properties. Observations were made from hydraulic bulge tests of AA1050/AA6016 laminates, wherein ARB-processed specimens showed higher burst pressures S. Roy Á B. R. Nataraj Á S. Suwas (&) Á S. Kumar Á K. Chattopadhyay Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India e-mail: satyamsuwas@materials.iisc.ernet.in 123 J Mater Sci (2012) 47:6402–6419 DOI 10.1007/s10853-012-6567-z