Hot deformation behavior and processing map of Mg-2Zn-1Al-0.2RE alloy

Niu, Yanxia; Hou, Jian; Ning, Fangkun; Chen, Xingrui; Jia, Yonghui; Le, Qichi

doi:10.1016/j.jre.2019.09.007

Cited by 35 publications

(6 citation statements)

References 41 publications

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“…The massive LPSO phase at the grain boundary was precipitated and accompanied by the grain boundary deformation of the large grains, which were compressed into strips and then broken. Due to the occurrence of DRX during the compression, the microstructure of the alloy exhibited a bimodal microstructure, but the DRX was different at different strain rates [ 21 , 22 ]. With the decrease in the strain rate, the degree of recrystallization gradually increased.…”

Section: Resultsmentioning

confidence: 99%

Effect of Deformation Parameters on Recrystallization Behavior and Long-Period Stacking-Ordered Phase of Mg-9Gd-4Y-2Zn-0.5Zr Alloy

et al. 2022

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In this study, a Mg-9Gd-4Y-2Zn-0.5Zr (wt.%) alloy was subjected, after solution treatment, to hot compression deformation at different temperatures (350 °C, 400 °C and 450 °C) and different strain rates (0.001 s−1, 0.01 s−1, 0.1 s−1 and 0.5 s−1) on a Gleeble-3800 thermal simulator. The evolution of the stress–strain curves under different conditions was compared. The changes in microstructure caused by the different deformation parameters and the change law of the long-period stacking-ordered (LPSO) phase during compression were observed and analyzed by optical microscope (OM) and scanning electron microscope (SEM). The results show that with the increase in the deformation temperature and the decrease in the strain rate, the degree of dynamic recrystallization (DRX) gradually increased, and the morphology of the phase also changed through, for example, twist fracture. The continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) mechanisms activated during the thermal deformation process can effectively refine the grains and weaken the texture in the alloy.

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Section: Resultsmentioning

confidence: 99%

Effect of Deformation Parameters on Recrystallization Behavior and Long-Period Stacking-Ordered Phase of Mg-9Gd-4Y-2Zn-0.5Zr Alloy

et al. 2022

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“…During dynamic recrystallization materials, such as close-packed hexagonal materials, with the increase of strain, the flow stress increased due to the occurrence of dynamic recovery (DRV) until the critical strain( ε c ) was reached, at which the generation and annihilation of dislocations offset each other. With further straining, the dynamic recrystallized material exhibited a peak ( σ p ) above critical stress ( σ c ), at which dynamic recrystallization initiated followed by a work softening process, as shown by the black line in Figure 3 f. However, the low stacking fault energy (face-centered cubic) metals reached steady-state stress under critical strain ( ε DRV ) during deformation, and a further increase in strain (above σ p ) did not result in a decrease in stress, shown by a pink dotted line in Figure 3 f. In this Figure, the curves can be divided into four stages [ 26 ]. Stage(I) is the elastic deformation segment; the flow stress increased almost linearly where the sub-grains formed due to dislocation generation and multiplication.…”

Section: Resultsmentioning

confidence: 99%

“…Compression temperature and strain rate have a significant influence on the variation trend of flow stress and the occurrence of DRX. The relationship between strain rate, flow stress, and compression temperature was proposed by Arrhenius and described by the most common constitutive equation model as follows [ 24 , 26 , 35 ]:

where

and T are strain rate and compression temperature, R and Q are ideal gas constant (8.31 J/mol) and deformation activation energy, n is the stress exponent, A and α are dimensionless material constants. When x is very small, sinh( x ) approximately is x , when x is very large, sinh( x ) about equals e x / 2 by the mathematical analysis.…”

Section: Resultsmentioning

confidence: 99%

Constitutive Model and Recrystallization Mechanism of Mg-8.7Gd-4.18Y-0.42Zr Magnesium Alloy during Hot Deformation

Zhang

et al. 2022

Materials

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The hot deformation behavior of Mg-8.7Gd-4.18Y-0.42Zr alloy was investigated by uniaxial hot compression tests at 300–475 °C with strain rates of 0.002–10 s−1. The average activation energy was calculated as 227.67 KJ/mol and a constitutive relation based on the Arrhenius equation was established in this study. The results show that Mg-8.7Gd-4.18Y-0.42Zr magnesium alloy is a strain rate and temperature-sensitive material. When the temperature is constant, the flow stress increases with the increase of strain rate, while when the strain rate is stable, the flow stress decreases with the increase of temperature. DRX is the main softening mechanism of the alloy, including continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). Meanwhile, the DRX grains nucleate preferentially at the twin intersections in the parent grains under the deformation condition below 300 °C and gradually expand outward with the increase of strain. When the compression temperature is above 400 °C, DRX grains nucleate preferentially at the original grain boundary and then gradually expand inward with the increase of strain. The optimum deformation conditions of the studied alloy are performed at 400–450 °C and 0.002–0.02 s−1 by a comprehensive comparison of the hot processing map, microstructure refinement, and formability.

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“…Therefore, this section will construct the constitutive equation for the alloy based on the peak stress. The theory can be expressed as follows: 19)…”

Section: Construction Of Constitutive Equation Based On Peak Stressesmentioning

confidence: 99%

Hot Deformation Behaviour and Deformation Microstructure of an Al–Zn–Ce Damping Alloy

Wang,

Zhang,

2023

Mater. Trans.

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A damping alloy with a nominal composition of 50Al-49.9Zn-0.1Ce (at%) was tested in hot compression (60% depression) using a Gleeble-3800 thermomechanical simulator at deformation temperatures and strain rates ranging from 573 to 648 K and 0.01 to 10 s ¹1 , respectively. According to the true stress-strain curves, two constitutive equation models based on peak stress and strain compensation were constructed. The microstructure of the alloy after deformation was characterized and analyzed by means of X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results show that the flow stress increases with decreasing deformation temperature and increasing strain rate. The theoretical predictions of the constitutive equation model at low temperature and high strain rate are well fitted to the measured values with low average absolute relative errors. At low strain rates and high temperatures, the ¡ + © eutectoid structure tends to transform from lamellar to granular morphologies, which is accompanied by the increased sizes of ¡ and © phases. Also, the obvious dissolution of © into ¡ phase has been occurred and some tiny holes induced by thermal-force coupling have been formed during compression. In this work, the Al-Zn-Ce damping alloy is more suitable for thermomechanical processing at relatively lower temperatures and meanwhile higher strain rates (such as at 573 K/0.1 s ¹1 , 573 K/10 s ¹1 and 623 K/10 s ¹1 ).

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Hot deformation behavior and processing map of Mg-2Zn-1Al-0.2RE alloy

Cited by 35 publications

References 41 publications

Effect of Deformation Parameters on Recrystallization Behavior and Long-Period Stacking-Ordered Phase of Mg-9Gd-4Y-2Zn-0.5Zr Alloy

Effect of Deformation Parameters on Recrystallization Behavior and Long-Period Stacking-Ordered Phase of Mg-9Gd-4Y-2Zn-0.5Zr Alloy

Constitutive Model and Recrystallization Mechanism of Mg-8.7Gd-4.18Y-0.42Zr Magnesium Alloy during Hot Deformation

Hot Deformation Behaviour and Deformation Microstructure of an Al–Zn–Ce Damping Alloy

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