Influence of the Processing Temperature on the Microstructure, Texture, and Hardness of the 7075 Aluminum Alloy Fabricated by Accumulative Roll Bonding

Abstract

The 7075 alloy is an Al-Zn-Mg-Cu wrought age-hardenable aluminum alloy widely used in the aeronautical industry. The alloy was accumulative roll bonded at 300°C (573 K), 350°C (623 K), and 400°C (673 K), and the microstructure, texture, and hardness were investigated. Cell/(sub)grain size in the nanostructured range, typical b-fiber rolling texture, and homogeneous hardness through thickness were determined in all cases. Misorientation was different at each processing temperature. At 400°C, the presence of elements in solid solution and the partial dissolution of the hardening precipitates lead to a poorly misoriented microstructure with a high dislocation density and a homogeneous b-fiber texture of low intensity, typical of intermediate degrees of rolling. At 350°C and 300°C, highly misoriented microstructures with smaller dislocation density and intense heterogeneous b-fiber rolling texture are observed, especially at 350°C, wherein the degree of dynamic recovery (DRV) is higher. Hardness of the accumulative roll bonded samples is smaller than that of the starting material due to particle coarsening, and it is affected by solid solution and/or by fine precipitates produced by reprecipitation of the elements in solid solution.

Texture development in Al/Al2O3 MMCs produced by anodizing and ARB processes

“…Moreover, continuous rolling mills can be readily used in industry for ARB. For these reasons, ARB is perhaps the most promising SPD process for industrial practices [7].…”

Strain Variations on Rolling Condition in Accumulative Roll-Bonding by Finite Element Analysis

“…There are numerous reports on microstructure evolution in various sheet materials by ARB process (Hidalgo et al, 2010;Kolahi et al, 2009;Xing et al, 2002). In most papers, a rolling by a 50% reduction in thickness is conducted without lubricant, and equivalent strain calculated simply from reduction in thickness has been used regardless of a high friction condition.…”

Evolution of the microstructure, texture and creep properties of the 7075 aluminium alloy during hot accumulative roll bonding

“…According to these studies, grain refinement takes place in a gradual manner which can be characterized as continuous recrystallization. In the particular case of aluminium, studies on the microstructural evolution during ARB have been widely performed on pure aluminium [6] and several alloys such as AA3003 [5], AA6061 [4] and AA8006 [8], while a few studies have been performed on the aeronautical 7075 Al alloy [10][11][12], despite the large advantages that would arise from refining its microstructure. A previous work [10] revealed that, as a high-strength alloy, the 7075 Al alloy needs to be processed at a minimum temperature of 300ºC in order to attain sufficient bonding and good workability.…”