scholarly journals Hot Deformation Behavior of a 2024 Aluminum Alloy Sheet and its Modeling by Fields-Backofen Model Considering Strain Rate Evolution

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 243 ◽  
Author(s):  
Zhubin He ◽  
Zhibiao Wang ◽  
Yanli Lin ◽  
Xiaobo Fan

The deformation behavior of a 2024 aluminum alloy sheet at elevated temperatures was studied by uniaxial hot tensile tests over the nominal initial strain rate range of 0.001–0.1 s−1 and temperature range of 375–450 °C. In order to analyze the deformation behavior with higher accuracy, a digital image correlation (DIC) system was applied to determine the strain distribution during hot tensile tests. Local stress-strain curves for different local points on the specimens were calculated. The strain rate evolution of each point during the tensile tests was investigated under different deformation conditions. Then, an improved Fields–Backofen (FB) model, taking into account the local strain rate evolution instead of the fixed strain rate, was proposed to describe the constitutive behaviors. It has been found that obvious non-uniform strain distribution occurred when the true strain was larger than 0.3 during hot tensile tests. The strain rate distribution during deformation was also non-uniform. It showed increasing, steady, and decreasing variation tendencies for different points with the increasing of strain, which led to the local flow stress being different at different local points. The flow stresses predicted by the improved FB model showed good agreement with experimental results when the strain rate evolutions of local points during tensile tests were considered. The prediction accuracy was higher than that of traditional FB models.

2018 ◽  
Vol 920 ◽  
pp. 236-243
Author(s):  
Peng Zhou ◽  
Lei Deng ◽  
Xin Yun Wang

To study microstructure and texture evolution of 2024 aluminum alloy sheet under different loading conditions, thermal tensile and compression experiments of 2024 aluminum alloy rolled sheets were carried out at temperatures ranging from 300 °C to 450 °C and under strain rates ranging from 0.001 s-1 to 0.1 s-1. During tensile deformation, the HABs of original grains are directly elongated until abruption. DRX process occurs during compression. Dislocations appear during deformation, migrate and accumulate into LABs, and then rotate into HABs to form new grain.The three-dimensional orientation distribution functions (ODFs) in different stress states were measured, with related texture types and distribution laws compared. According to ODFs with a constant φ2, the deformation texture of {011} <100>Goss texture is gradually strengthened during thermal tension at high temperature and low strain rate (450°C/0.001s-1). The deformation texture of {011} <100>Goss texture is weakened with the strain increasing. Furthermore, the increase of deformation temperature or the decrease of strain rate slows down the weakening process of {011} <100> Goss texture, which is attributed to the recrystallization behavior during tensile deformation. Besides, since the recrystallization process proceeds more completely during hot compression, it produces a quasi-random texture.


Author(s):  
Kamyar Ghavam ◽  
Reza Bagheriasl ◽  
Michael J. Worswick

In this paper, a finite element model is developed for 3000 series clad aluminum alloy brazing sheet to account for temperature and strain rate dependency, as well as plastic anisotropy. The current work considers a novel implementation of the Barlat YLD2000 yield surface in conjunction with the Bergstrom hardening model to accurately model aluminum alloy sheet during warm forming. The Barlat YLD2000 yield criterion is used to capture the anisotropy while the Bergstrom hardening rule predicts the temperature and strain rate dependency. The results are compared with those obtained from experiments. The measured stress–strain curves of the AA3003 aluminum alloy sheet at elevated temperatures and different strain rates are used to fit the Bergstrom parameters and measured R-values and directional yield stresses are used to fit the yield function parameters. Isothermal uniaxial tensile tests and nonisothermal deep drawing experiments are performed and the predicted response using the new constitutive model is compared with measured data. In simulations of tensile tests, the material behavior is predicted accurately by the numerical models. Also, the nonisothermal deep drawing simulations are able to predict the load–displacement response and strain distributions accurately.


2014 ◽  
Vol 548-549 ◽  
pp. 297-300
Author(s):  
Dae Yong Kim ◽  
Hyeon Il Park ◽  
Ji Hoon Kim ◽  
Sang Woo Kim ◽  
Young Seon Lee

Studies on electromagnetic impact welding between similar or dissimilar flat sheet metals using the flat one turn coil have been recently achieved. In this study, three dimensional electromagnetic-mechanical coupled numerical simulations are performed for the electromagnetic impact welding of aluminum alloy sheets with flat rectangular one turn coil. The deformation behavior during impact welding was examined. The effect of process parameters such as charge voltage, standoff distance and gap distance were investigated.


Applied laser ◽  
2011 ◽  
Vol 31 (5) ◽  
pp. 361-368
Author(s):  
张凤英 Zhang Fengying ◽  
谭华 Tan Hua ◽  
陈静 Chen Jing ◽  
邓娟莉 Deng Juanli

2015 ◽  
Vol 21 (2) ◽  
pp. 365-373 ◽  
Author(s):  
Gaoshen Cai ◽  
Lihui Lang ◽  
Kangning Liu ◽  
Sergei Alexandrov ◽  
Dongxing Zhang ◽  
...  

AIP Advances ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 025023 ◽  
Author(s):  
Gaoshen Cai ◽  
Xiaojun Zhou ◽  
Lihui Lang ◽  
Sergei Alexandrov

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