scholarly journals Hot Deformation Behavior of Homogenized Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr Alloy via Hot Compression Tests

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2282 ◽  
Author(s):  
Zhimin Zhang ◽  
Zhaoming Yan ◽  
Yue Du ◽  
Guanshi Zhang ◽  
Jiaxuan Zhu ◽  
...  

Mg-Gd-Y-Zn-Zr Mg alloys show excellent performance in high-end manufacturing due to its strength, hardness and corrosion resistance. However, the hot deformation and dynamic recrystallization (DRX) behaviors of Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr were not studied. For this article, hot compression behavior of homogenized high rare-earth (RE) content Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr (wt%) alloy was investigated by using the Gleeble-3500D thermo-simulation test machine under the temperature of 350–500 °C and the strain rate of 0.001–1 s−1. It was found that the high flow stress corresponded to the low temperature and high strain rate, which showed DRX steady state curve during the hot compression. The hot deformation average activation was 263.17 kJ/mol, which was obtained by the analysis of the hyperbolic constitutive equation and the Zener-Hollomon parameter. From observation of the microstructure, it was found that kink deformation of long period stacking ordered (LPSO) phase was one of the important coordination mechanisms of hot deformation at low temperature. The processing map with the strain of 0.5 was established under the basis of dynamic material model (DMM); it described two high power dissipation domains: one appearing in the temperature range of 370–440 °C and the strain rate range of 0.001–0.006 s−1, the other appearing in the temperature range of 465–500 °C and strain rate range of 0.001–0.05 s−1, in which dynamic recrystallization (DRX) mainly ocurred. The highest degree of DRX was 18% from the observation of the metallographic.

Author(s):  
YL Wang ◽  
Y Li ◽  
H Zhang ◽  
JL Yang ◽  
XD Ma ◽  
...  

Quasi-static hot deformation behavior of a novel third-generation Ni-based powder metallurgy superalloy A3 was investigated by hot compression tests and microscopy. The activation energy for hot working of the experimental alloy was about 867 kJ/mol. An instability domain existed in the processing map when the strain was 0.2, implying a plastic instability at the temperature range of 1080–1100°C and the strain rate range of 0.016–0.1 s−1. The power dissipation efficiency in processing maps indicated that optimum parameters for large deformation could be controlled at the temperature range of 1000–1030°C and the strain rate range of 0.001–0.01 s−1. It provided a reliable suggestion for hot processing during the manufacturing of such superalloy.


2012 ◽  
Vol 538-541 ◽  
pp. 1257-1261
Author(s):  
Sheng Li Guo ◽  
Peng Du ◽  
Xiao Ping Wu ◽  
De Fu Li

The hot deformation behavior of Zn91.8-Cu8-Cr0.2 (in wt.%) was investigated by means of hot compression tests in the temperature range of 230-380 °C and strain rate range of 0.01 - 10 s-1. The constitutive equation and processing maps were developed. The influence of strain on the flow stress was studied by considering the effect of the strain on material constants. The stress-strain curves obtained by the constitutive equation are in good agreement with experimental results. The proposed constitutive equations can be used for the analysis problem of hot forming processes. The processing maps have exhibited a domain, which is optimum processing window for hot working, in the temperature range of 310 - 380 °C and strain rate range of 0.01-1 s-1 corresponding to the higher efficiency of power dissipation. The large regime of flow instability is observed at high strain rate. The instability regime should be avoided during hot deformation processing.


2004 ◽  
Vol 449-452 ◽  
pp. 577-580
Author(s):  
Young Sang Na ◽  
Young Mok Rhyim ◽  
J.Y. Lee ◽  
Jae Ho Lee

In order to quantitatively analyze the critical strain for the initiation of dynamic recrystallization in Ni-Fe-based Alloy 718, a series of uniaxial compression tests was conducted in the temperature range 927°C - 1066°C and the strain rate range 5 x 10-4s-1- 5 s-1with varying initial grain size. The critical strains were graphically determined based on one parameter approach and microscopically confirmed. The effect of γ'' (matrix-hardening phase) and δ (grain boundary phase)on the critical strain was simply discussed. The constitutive model for the critical strain of Alloy 718 was constructed using the experimental data obtained from the higher strain rate and the temperature range between 940°C and 1040°C.


2016 ◽  
Vol 35 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Yongkang Liu ◽  
Zongmei Yin ◽  
Junting Luo ◽  
Zhang Chunxiang ◽  
Yanshu Zhang

AbstractIsothermal compression tests were conducted on A100 steel using a Gleeble 1500 thermal simulator at a temperature range of 900–1,200°C and strain rate range of 0.001–3 s−1. Results show that the A100 steel has higher strength than the Aermet 100 steel at high temperatures. Constant values, such as A, α, and n, and activate energy Q were obtained through the regression processing of the stress–strain data curves under different strains. A set of constitutive equations for A100 steel was proposed by using an Arrhenius-type equation. The optimum processing craft ranges for A100 steel based on the analysis of the hot working diagram and deformation mechanism are as follows: temperature range of 1,000–1,100°C and strain rate range of 0.01–0.1 s−1. The average grain size within this working range is 7–22.5 μm.


2012 ◽  
Vol 578 ◽  
pp. 202-205
Author(s):  
Guo Qing Lin

The hot deformation behavior of Zr-4 alloy was studied in the temperature range 650-900°C and strain rate range 0.005-50s-1 using processing maps. The processing maps revealed three domains: the first occurs in the temperature range 780-820°C and strain rate range 0.005-0.05s-1, and has a peak efficiency of 45% at 790°C and 0.005s-1; the mechanism is the dynamic recrystallization. The second occurs in the temperature range greater than 900°C and strain rate range 0.05-0.8s-1, and has a peak efficiency of 40% at 900°C and 0.5s-1, which are the domains of dynamic recovery. In addition, the instability zones of flow behavior can also be recognized by the maps in the temperature range 650-780°C and strain rate range 0.01-0.1s-1, which should be strictly avoided in the processing of the material. Zr-4 alloy is the material for pressure tube applications in nuclear reactors and has better strength and a lower rate of hydrogen uptake compared to other materials under similar service conditions.


2011 ◽  
Vol 189-193 ◽  
pp. 2847-2850
Author(s):  
Ming Yang ◽  
Yong Shun Yang ◽  
Dong Dong Yang

Using the compression tests on a Gleeble-1500 thermo-mechanical simulator to study the dynamic recrystallization behaviours of AZ80 magnesium alloy in the temperature range of 593-683K and strain rate range of 0.01-10s-1. By the analysis of the dynamic recrystallization kinetics, the Avrami exponent (m) and the constant (k) have been determined, and they aren’t constant and depend on the dimensionless parameter(Z/A).


2015 ◽  
Vol 816 ◽  
pp. 810-817
Author(s):  
Yong Biao Yang ◽  
Zhi Min Zhang ◽  
Xing Zhang

The hot deformation behaviors of Aluminum alloy C919 were studied in the present investigation. The hot compression tests for C919 were carried out in the temperature range of 350°C~470°C and strain rates range of 0.001s-1~1s-1 using GLEEBLE-1500 thermal simulate testing machine. Optical microscopy (OM) was used for the microstructure characterization. The experimental results showed that the flow stress of C919 aluminum alloy decreased with increasing temperature and decreasing strain rates and the flow stress curves tended to increase at a strain rate of 1s-1 with increasing strain, while the flow stresses kept with increasing strain at lower strain rate. The alloys were more prone to dynamic recrystallization with decreasing strain rates during hot deformation. The hot compression behavior of C919 aluminum alloy can be described as hyperbolic sine function corrected Arrhenius relation. The processing maps for the alloy were built at a strain of 0.6. The instability deformation domain occurred at temperatures range from 350°C and 380°C and at a strain rate of 0.1-1s-1. Based on the processing maps and microstructure observations, the optimum hot-working parameters were determined to be at a temperature of 470°C in the strain rate range from 0.1-0.01s−1 for the C919 aluminum alloy.


2013 ◽  
Vol 815 ◽  
pp. 37-42 ◽  
Author(s):  
Yu Juan Guo ◽  
Lei Deng ◽  
Xin Yun Wang ◽  
Jun Song Jin ◽  
Wen Wu Zhou

The hot deformation behavior of 7050aluminum alloy was investigated by hot compression tests in the temperature range of 573-773K and the strain rate ranging from 0.001s-1to 10 s-1.The flow curves showed that the flow stresses increase with the increase of strain rate or the decrease of temperature.In order to determine the optimal processing conditions, hot processing maps were established based on experimental data and Dynamic Materials Model. The processing maps indicate that instability occur at low temperature and high strain rate. The optimum hot working region is the domain in the temperature range of 673-723K and strain rate range of 0.001-0.01 s-1,where typical recrystallization was observed in the optical microstructures.


2011 ◽  
Vol 687 ◽  
pp. 467-473
Author(s):  
Ji Heng Li ◽  
Xue Xu Gao ◽  
Jie Zhu ◽  
Xiaoqian Bao ◽  
Mao Cai Zhang

In this work, the hot deformation behavior of Fe83Ga17alloy with 1.0 at.% B addition was investigated by plane strain compression tests on a Gleeble-1500 hot simulation test machine in the deformation temperature range of 350 to 900 °C. The effects of strain rate range 0.1-10 s-1on flow stress and microstructure were also studied. It was indicated that as the temperature increases, significant softening of the material occurred, and significant dynamic recovery at low strain rate (0.1 s-1) and recrystallization at high strain rate (10 s-1) occurred during deformation at 900 °C. The results also suggested that deformation mechanism under low temperature (~500°C) was twinning. The hot deformation activation energy (Q) of the Fe83Ga17with 1.0 at.%B alloy was calculated to be 295.3 kJ/mol.


2012 ◽  
Vol 490-495 ◽  
pp. 3423-3426 ◽  
Author(s):  
Xin Zhao ◽  
Hong Zhao ◽  
Rui Zhang

The hot deformation characteristics of TC18 titanium alloy were studied in the temperature range 750-850°C and strain rate range 0.001-1 s-1 by using hot compression tests. Processing maps for hot working are developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate. The results reveal that the flow stress of TC18 is sensitive to strain rate. Processing map at stain of 0.6 reveals two domains: one is centered at 750°C and 0.001s-1; another is centered at 850°C and 0.001s-1. The maximum efficiency is more than 60%. According to the maps, the zone with the temperature range of 750-850°C and strain rate range of 0.01-0.001s-1 may be suitable for hot working


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