•The aluminum alloy 6082 in this study is an extruded material after aging.•Compare the traditional constitutive equation of the material and the strain-compensated Arrhenius model with the newly ...established PSO-BP network model.•Use statistical analysis methods for data analysis.
It is important to model the flow behavior of an aged aluminum alloy AA6082 as an extrusion material before design and optimize of the forming process. In this study, the isothermal compression tests were carried out on Gleeble-3800 thermal simulator in the temperature range of 423−773 K and the deformation condition of 0.01–1.0 s−1 to study the cold temperature and hot deformation behavior of aluminum alloy AA6082. Considering the experimental error, the discussion based on friction and temperature correction is carried out. According to the modified data, based on the traditional Arrhenius constitutive model, a method combining the strain compensation Arrhenius model and PSO-BP neural network was proposed to describe the flow behavior of aluminum alloy AA6082. The prediction ability and stability of the model are evaluated by using the linear correlation coefficient(r), the average relative errors (AARE), the Root mean square errors(RMSE) and the relative errors (RE) in statistical analysis. The results show that the 3-10-8-1 double hidden layer neural network model based on PSO-BP has higher effect in predicting the flow characteristics of aging aluminum alloy AA6082 than that of Arrhenius model based on strain compensation. The linear correlation coefficient, mean relative error and root mean square error are 0.9996 %, 2.001 % and 1.665 MPa respectively.
The influences of process parameters on mechanical properties of AA6082 in the hot forming and cold-die quenching (HFQ) process were analysed experimentally. Transmission electron microscopy was used ...to observe the precipitate distribution and to thus clarify strengthening mechanism. A new model was established to describe the strengthening of AA6082 by HFQ process in this novel forming technique. The material constants in the model were determined using a genetic algorithm tool. This strengthening model for AA6082 can precisely describe the relationship between the strengths of formed workpieces and process parameters. The predicted results agree well with the experimental ones. The Pearson correlation coefficient, average absolute relative error, and root-mean-square error between the calculated and experimental hardness values are 0.99402, 2.0054%, and 2.045, respectively. The model is further developed into an FE code ABAQUS via VUMAT to predict the mechanical property variation of a hot-stamped cup in various ageing conditions.
Friction Stir Welding (FSW) is a relatively new process which has proved to be a much more viable joining process for all Aluminium Alloys than earlier techniques, such as Metal Inert Gas, Tungsten ...Inert Gas, Laser Welding and Resistance Welding. Friction Stir Welding is the fastest evolving joining technology and the principal prospective technique for implementing integral fuselage structure in aircraft manufacturing. Friction Stir Welding is a solid-state joining process that uses a non-consumable tool to join two facing work pieces without melting the work piece material. The main objective of the work is to study the effect of mechanical properties like Hardness, Tensile strength along with Microstructure by varying the tool rotational speed of 500 rpm, 710 rpm, 1000 rpm and 1400 rpm during the Friction Stir Welding of Aluminium Alloy 6082 with different reinforcement percentages of 5%, 10% and 15% of Aluminium Oxide (Al2O3). FSW process parameters were optimized using the ANOVA method and Response Surface Methodology to determine the optimum values of Tensile strength of the joints.
Fifteen-millimeter-thick aluminum alloy AA6082-T651 extruded flats were friction-stir-welded by using three different types of tool pin profiles, i.e., (1) conical with only left-hand threads (CL), ...(2) conical with both left-hand and right-hand threads (CLR), and (3) conical cam-tri-flute with left-hand threads (CTFL) up to a height of 6 mm from the pin tip. The microstructures and the mechanical properties across the weld thickness were characterized. Tunneling defect was found at the weld-bottom for the CL tool pin profile and at the weld-top for the CLR pin profile. The reasons behind the formation of such defects have been analyzed and discussed. On the other hand, a defect-free joint was obtained with the CTFL pin profile. Tensile test samples were machined from top, middle, and bottom sections of the welds, and tensile strengths were measured for all the sections to determine the joint efficiencies. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were employed to identify and study the morphology of the coarse phase particles present in the base material and in different regions of the welds. These results were correlated with the microhardness contours plotted across the weld cross section.
The fabrication and processing of aluminum alloys can result in the formation of different grain sizes and textures within the material. The effects of these differences on the corrosion behaviour of ...the commercially available alloy AA6082 have been investigated. The results of the macro‐ and microelectrochemical investigations have been compared with each other and with the resulting corrosion appearance. The observed corrosion damage is not always consistent with the measured corrosion and pitting potential. In the finer‐grained part, with a strongly preferred orientation of (002) planes parallel to the sample surface, less corrosion damage could be observed than in the coarser‐grained part. However, microelectrochemical measurements show a slightly lower pitting potential in the finer‐grained part, so that pitting is likely to start earlier in this area.
Durch Herstellung und Verarbeitung von Aluminiumlegierungen werden Korngröße und Textur beeinflusst. Die Auswirkungen dieser Unterschiede auf das elektrochemische Korrosionsverhalten der kommerziell erhältlichen Legierung EN AW‐6082 wurden untersucht. Die Ergebnisse der makro‐ und mikroelektrochemischen Untersuchungen werden gegenübergestellt und mit den resultierenden Korrosionserscheinungen verglichen. Dabei zeigt sich, dass der beobachtete Korrosionsschaden nicht immer mit den gemessenen Korrosions‐ bzw. Lochfraßpotenzialen im Einklang steht. Im feinkörnigeren Bereich mit einer starken Vorzugsorientierung der (002)‐Netzebenen parallel zur Probenoberfläche finden sich geringere Korrosionsschäden als im grobkörnigeren Bereich. Allerdings zeigen mikroelektrochemische Messungen ein etwas niedrigeres Lochfraßpotenzial für den feinkörnigeren Bereich, was auf früher einsetzende Lochkorrosion hindeutet.
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