Research On The Influence Of Process Parameters On Age Forming Formability Of 7075 Aluminum Alloy Components

In this work, experimental investigations of processing parameters were conducted for creep age forming artificially aged 7075 aluminum alloy components, and thus the combined influences of aging temperature(T), aging time(t) and die surface radius(R) were reported on springback of samples after creep age forming by orthogonal experiments; the effects of aging temperature and aging time on microstructure, springback and mechanical properties were studied by different system experiments under the ageing processes; the study on creep age forming of Friction Stir Welded(FSW) components were investigated by the optimal process parameters of non-welded samples, which provides a new and low-cost method for integral panel.The orthogonal test results show that, the forming parameters of aging temperature, aging time and die surface radius, in the order named, have significant effects on springback rate, and with an aging temperature of 190℃, an aging time of 15 hours, and a die surface radius of 300 mm, the deformed samples exhibit a better forming efficiency, and the springback rate reaches 29.43%. The springback analyses of orthogonal experiments for 7075 aluminum alloy sheets, obtain a quantitative relationship between each factor(T, t, R) and springback rate(Sp), and it was proved to be exactly lately.The springback analyses of different system creep age forming experiments show that, the creep age forming formability of 7075 aluminum alloy components are greatly concerned with the processing parameters. With the increasing of ageing temperature and ageing time, the size of the η’ particle and conductivity tends to increase, while the springback rate, tensile properties and hardness are decreasing. Furthermore, the alloy fracture mode is associated with ageing conditions. At the early over-aged stage, the fracture mode is the mixed type of transgranular fracture and intergranular fracture, while the trend of dimple fracture increases under over-aged stages. Through the analysis of springback rate data, fitted linear regression lines of 7075 aluminum alloy were found, including Sp(T), Sp(t), which verified the feasibility of the springback prediction. Considering the combined influences of forming precisions and mechanical properties on deformed samples, the best ageing temperature is 180℃, and an ageing time should not be longer than 16 hours for creep age forming of 7075 aluminum alloy sheets.With the optimal process parameters of non-welded samples after creep age forming, the study on creep age forming of FSW components under 180℃ and different aging time were obtained by mechanical loading setup. Results show that FSW technology has a significant impact on springback rate, microstructure and mechanical properties of 7075 aluminum alloy, the samples after creep age forming to achieve the desired requirements, and the best creep aging forming technology is 180℃, 12 h.The fitting equation between springback rate and process parameters provides a reference for the springback control technology and optimizes the process parameters of 7075 aluminum alloy; the research results not only guarantee the alloy performance but also achieve good artifacts shape, to meet the components’ shape and properties coordinatedly, and also establish an experimental basis for the FSW-based integral panel structures.