Accumulative roll bonding (ARB) introduced by Saito et al. [1] is one of the methods of severe plastic deformation (SPD), where high strains are introduced into metals and alloys to achieve an ultrafine grained (UFG) microstructure with grain sizes ranging between 1 mm and 100 nm. [2][3][4][5] Metals and alloys with UFG microstructure show a significant enhancement of hardness and yield stress (e.g. [6] ) with only a slightly decreasing and in case of some aluminum alloys even an increasing ductility compared to their conventional large grain-sized counterparts. [7][8][9] Compared to other SPD methods ARB has the special advantage of producing UFG bulk materials in form of sheets. As the processing is relatively simple, ARB can easily be integrated into process chains of conventional sheet processing.Due to their significantly higher specific strength, UFG materials have aroused attention in the automobile and aircraft industry. As high strength and light weight structural components, the use of UFG materials can lead to weight reduction and resource conservation.In this study sheets of UFG technically pure aluminum AA1050 and technically relevant age-hardening aluminum alloy AA6016 produced by ARB were investigated. The evolution of the microstructure as a function of ARB cycles was analyzed by electron backscatter diffraction (EBSD) with regard to grain size, aspect ratio, and misorientation. The evolution of the bulk texture and of the mechanical properties during the ARB process was studied by neutron diffraction and via tensile tests, respectively. COMMUNICATIONTexture, microstructure, and tensile behavior of technically pure aluminum AA1050 and of the age-hardening alloy AA6016 produced by accumulative roll bonding (ARB) were studied for different numbers of ARB cycles. After eight cycles an ultrafine grained microstructure with grain sizes of the order of 0.5 mm is reached. The grain size decreases with increasing alloying content. The texture consists of a major copper component and a minor brass component. The latter strengthens with alloying. Due to shear deformation in the surface region also a rotated cube component is found. It is stronger in the pure material and is partly added up in the bulk during ARB. Due to dislocation and grain boundary hardening the tensile strength increases with increasing ARB cycles following the Hall-Petch behavior while a moderate ductility is kept. Within the sheet plane no significant influence of the tensile direction on the observed mechanical properties was found.

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The paper aims to summarize the research on Laminar Metal Composites produced by Accumulative Roll Bonding. After some notes on the general subject, frequent material combinations and the issue of bonding are addressed. Then, the evolution of microstructure, texture, and mechanical properties typically observed in such materials is briefly summarized. Furthermore, the crucial aspect of layer continuity is discussed. In the main part, detailed experimental insight is provided for three representatives of different structural developments, namely Al2N/Al5N, Cu/Nb, and Ti/Al. The chosen systems represent different levels of component dissimilarity, as Al2N/Al5N is a combination of the same face centered cubic metal with varying purity while Cu/Nb and Ti/Al are combinations of face centered cubic with both body centered cubic and hexagonal close packed metals, respectively. As the layer thicknesses span different ranges, the composites also illustrate both the opportunities and experimental challenges of ARB Laminar Metal Composites.bonding (in the following, those processes will be referred to "ARB"), often supplemented by annealing and rolling steps. Naturally, a high percentage of the scientific attention regarding LMCs is bestowed on Al alloys, for example, [7,25,[43][44][45][46][47][48][49][50] whose assets are excellent formability and corrosion resistance while being low in both weight and price.Al alloys are frequently combined in order to improve specific properties, for example, [51][52][53][54][55] A strong but corrosion susceptible Al alloy of series 2xxx, for example, benefits from the combination with a less strong but corrosion resistant alloy of series 6xxx. [50] Likewise, in LMCs of series 5xxx and 6xxx, both surface quality and weldability are improved due to the reduction of the PLC-effect [53] and hot cracking, [55] respectively.By combining Al with both Fe [56][57][58] or Cu, [45,59] the magnetic properties of the former and the electrical properties of the latter can be used to produce LMCs with potential in microelectronics and in electrical power industry, [60] respectively. Other components in LMCs with Cu are Ag, [61] Zn, [62] both Zn and Al, [63] and both Al and Ni. [64] Nb receives major scientific attention due to its superconducting properties, which work especially well in a finelayered structure with Cu or Al, [65] which are chosen for their low solubility in Nb and the absence of mutual intermetallics. In contrast, other LMCs are produced especially for intermetallic transition, for instance Al/Fe, [57,58,66] Al/Mg, [43,44] Al/Ti, [67][68][69][70][71] Al/Ni, [72,73] Ti/Nb, [74] or Ti/Al/Nb. [74] When high specific strength in combination with sufficient formability and ductility is the foremost requirement, Al is often combined with high-strength partners such as steel, for example, [66,75] Mg, for example, [46,76,49] Ti, for example, [67][68][69]74,[77][78][79][80][81][82][83][84][85][86] as well as both Mg and Ti. [87] Furthermore, Ti is paired with Fe, [88,89] Cu, for example, [90,...

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