The strain rate and temperature dependence of the dynamic impact properties of 7075 aluminum alloy

2000 ◽  
Vol 100 (1-3) ◽  
pp. 116-122 ◽  
Author(s):  
Woei-Shyan Lee ◽  
Wu-Chung Sue ◽  
Chi-Feng Lin ◽  
Chin-Jyi Wu
2008 ◽  
Vol 584-586 ◽  
pp. 164-169 ◽  
Author(s):  
Krystof Turba ◽  
Premysl Malek ◽  
Edgar F. Rauch ◽  
Miroslav Cieslar

Equal-channel angular pressing (ECAP) at 443 K was used to introduce an ultra-fine grained (UFG) microstructure to a Zr and Sc modified 7075 aluminum alloy. Using the methods of TEM and EBSD, an average grain size of 0.6 1m was recorded after the pressing. The UFG microstructure remained very stable up to the temperature of 723 K, where the material exhibited high strain rate superplasticity (HSRSP) with elongations to failure of 610 % and 410 % at initial strain rates of 6.4 x 10-2 s-1 and 1 x 10-1 s-1, respectively. A strain rate sensitivity parameter m in the vicinity of 0.45 was observed at temperatures as high as 773 K. At this temperature, the material still reached an elongation to failure of 430 % at 2 x 10-2 s-1. These results confirm the stabilizing effect of the Zr and Sc additions on the UFG microstructure in a 7XXX series aluminum alloy produced by severe plastic deformation.


2014 ◽  
Vol 626 ◽  
pp. 50-56
Author(s):  
Woei Shyan Lee ◽  
Mao Hung Liu

The effect of directional grain structure and strain rate on the impact properties and dislocation substructure of 6061-T6 aluminum alloy is studied. Impact tests are performed at strain rates ranging from 1x103 to 5x103s-1 using a split Hopkinson pressure bar system. Cylindrical specimens are prepared from the rolled plates in longitudinal direction, transverse direction and through-thickness direction, respectively. The results show that the flow stress is strongly dependent on the strain rate and displays complex variations with grain structure direction. The flow stress increases with increasing strain rate. For all tested strain rates, the flow stress is the highest in the transverse specimen, followed by the through-thickness specimen and longitudinal specimen. However, at the strain rate of 5x103s-1, the flow stress in longitudinal specimen is higher than that in through-thickness specimen due to the change of dislocation multiplication rate. The plastic flow occurs within the deformation regions, and becomes more pronounced at high strain rates, especially for the longitudinal specimen. Dislocation density increases markedly with increasing strain rate. Strengthening effect is the highest in the transverse specimen, followed by the longitudinal specimen and through-thickness specimen.


2019 ◽  
Vol 5 (1) ◽  
pp. 105-114
Author(s):  
C. J. T. Mason ◽  
P. G. Allison ◽  
O. L. Rodriguez ◽  
D. Z. Avery ◽  
B. J. Phillips ◽  
...  

2017 ◽  
Vol 36 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Guo-zheng Quan ◽  
Zhen-yu Zou ◽  
Tong Wang ◽  
Bo Liu ◽  
Jun-chao Li

AbstractIn order to investigate the hot deformation behaviors of as-extruded 7075 aluminum alloy, the isothermal compressive tests were conducted at the temperatures of 573, 623, 673 and 723 K and the strain rates of 0.01, 0.1, 1 and 10 s−1 on a Gleeble 1500 thermo-mechanical simulator. The flow behaviors showing complex characteristics are sensitive to strain, strain rate and temperature. The effects of strain, temperature and strain rate on flow stress were analyzed and dynamic recrystallization (DRX)-type softening characteristics of the flow behaviors with single peak were identified. An artificial neural network (ANN) with back-propagation (BP) algorithm was developed to deal with the complex deformation behavior characteristics based on the experimental data. The performance of ANN model has been evaluated in terms of correlation coefficient (R) and average absolute relative error (AARE). A comparative study on Arrhenius-type constitutive equation and ANN model for as-extruded 7075 aluminum alloy was conducted. Finally, the ANN model was successfully applied to the development of processing map and implanted into finite element simulation. The results have sufficiently articulated that the well-trained ANN model with BP algorithm has excellent capability to deal with the complex flow behaviors of as-extruded 7075 aluminum alloy and has great application potentiality in hot deformation processes.


2013 ◽  
Vol 699 ◽  
pp. 851-858 ◽  
Author(s):  
Zhi Chao Sun ◽  
Ji Lun Yin ◽  
He Yang

In this paper, two heat treatment routes have been carried out on a set of hot compressed 7075 aluminum alloy samples under different deforming conditions. By considering the hot deformation history the law of 7075 aluminum alloy’s microstructure evolution during these two heat treatments was studied and the microhardness was discussed. The results show that: (1) Static recrystallization in 7075 aluminum alloy was discovered during these two heat treatments (solid solution (465°C/40min) +T6 aging (120°C/24h) and solid solution (465°C/40min) + T73 aging (107°C/7h+177°C/7h)), its driving force was from stored energy which was not released in the previous thermal deformation process. Formation of recrystallized grain was due to subgrain merger mechanism. The static recrystallization became more remarkable as the hot deforming temperature decreasing. (2) The effects of strain rate on the statically recrystallized grain size of 7075 aluminum alloy were opposite under different deformation temperatures. Deformed at 450°C, during these two heat treatments the recrystallized grain size became smaller as the strain rate increasing. While deformed at 350°C, during solid solution+T73 aging treatment the recrystallized grain size increased as the strain rate increasing. (3) Under the same deformation conditions a difference existed in the microstructure of 7075 aluminum alloy after solid solution +T6 aging and solid solution + T73 aging, which was mainly due to different precipitated phases in the aging process. (4) Both two heat treatments can raise the microhardness of 7075 aluminum alloy remarkably. The hardness of 7075 aluminum alloy after solid solution+T73 aging was lower than that after solid solution+T6 aging, the main reason was the precipitated small  phase in the first stage of the T73 aging coarsen in the second stage of high-temperature aging process.


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