Dynamic recrystallization behaviour of Twin Roll Cast ZAX210 strips during hot deformation

Kittner, Kristina; Ullmann, Madlen; Henseler, Thorsten; Prahl, Ulrich; Kawalla, Rudolf

doi:10.37904/metal.2019.930

Cited by 4 publications

(5 citation statements)

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“…These form preferentially along the grain boundaries of the original structure and form a so-called necklace structure. The proportion of recrystallized grains is 18% for an equivalent logarithmic strain of 0.6 [ 17 ]. This mechanism of DRX is described for magnesium alloys by [ 42 , 43 , 44 ].…”

Section: Resultsmentioning

confidence: 99%

“…The histogram shows a significant peak at 86°, which suggests that extension twins are formed preferentially. Based on the initial texture [ 17 ], it can be assumed that the orientation of the crystals is favorable for the activation of extension twins. As deformation proceeds, it becomes apparent that misorientation angles between 35° and 45° occur more frequently ( Figure 5 b).…”

Section: Resultsmentioning

confidence: 99%

“…Our previous investigations on a twin-roll cast ZAX210 alloy during plane strain compression also showed an increased proportion of recrystallized grains at higher strain rates [ 17 ]. Thus, the aim of the present study is to investigate the microstructural and textural evolution of the ZAX210 alloy.…”

Section: Introductionmentioning

confidence: 93%

“…Further advantages in the combination of Zn and Ca in Mg alloys are the weakening of the basal texture and the improvement of formability. Consequently, various novel alloys have already been developed and investigated: Mg-2.4Zn-0.1Ag-0.1Ca-0.1Zr [ 12 ], Mg-3Zn-0.3Zr-0.25Ca-0.15Mn [ 13 ], Mg-1Sn-1Ca-0.5Zn [ 14 ] and Mg-2Zn-1Al-0.3Ca [ 15 , 16 , 17 , 18 , 19 , 20 ]. The investigations are mainly aimed at microstructure and texture development, considering the mechanical property profile and formability as a result of thermomechanical treatment.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural and Textural Investigation of an Mg-Zn-Al-Ca Alloy after Hot Plane Strain Compression

2022

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The formability of magnesium alloys can be significantly improved by Ca as an alloying addition. Compared to conventional alloy sheets such as AZ31, texture modification can be found in rolled Mg-Ca sheets, which reveal a randomized orientation distribution. The hot deformation behavior of a twin-roll cast and homogenized Mg-2Zn-1Al-0.3Ca (ZAX210) alloy was characterized during hot compression at a temperature of 350 °C and strain rates of 0.1 s−1 and 10 s−1. Electron backscatter diffraction (EBSD) analysis was performed in order to describe the microstructural and texture evolution. The ZAX210 alloy exhibits a pronounced dynamic recrystallization (DRX) behavior during compression at high strain rates, while at lower strain rates DRX hardly occurred. This effect can be attributed to different DRX mechanisms that take place as a function of strain rate. At low strain rates, DRX occurred locally at the grain boundaries of the original microstructure, forming a so-called necklace structure. Increasing strain rate results in an increased fraction of recrystallized grains from 18% (0.1 s−1) to 39% (10 s−1). The microstructure revealed that twin boundaries act as nucleation sites for the DRX (TDRX). The recrystallized areas exhibit a weaker texture compared to the deformed microstructure.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Microstructural and Textural Investigation of an Mg-Zn-Al-Ca Alloy after Hot Plane Strain Compression

2022

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“…During twin-roll casting, two kinds of textures typically arise: a deformation texture (due to the rolling process during TRC) or a casting texture (due to the directional growth of columnar grains). The WZ73 magnesium alloy did not offer the characteristic dendritic microstructure typified by columnar grains growing toward the center of the strip, as reported for other magnesium alloys [37]. Therefore, it was assumed that the texture after twin-roll casting resulted from the low degree of deformation during the rolling process.…”

Section: Texture Evolutionmentioning

confidence: 88%

Microstructure and Texture Evolution during Twin-Roll Casting and Annealing of a Mg–6.8Y2.5Zn–0.4Zr Alloy (WZ73)

et al. 2020

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In the present work, the microstructure and texture of a Mg–6.8Y–2.5Zn–0.4Zr sheet manufactured by twin-roll casting were investigated. The twin-roll cast state consisted of two apparent phases: the α-Mg matrix, which was made up of dobulites with an average grain size of approximately 50 µm and the LPSO (long-period stacking ordered) phase, which formed network-like precipitates along the grain boundaries. After twin-roll casting, annealing was carried out under conditions of different temperatures ranging from 450 °C to 525 °C and holding times between 2 h and 24 h. It was found that heat treatment led to the formation of a microstructure in which grains were apparent. Furthermore, it could be observed that high temperatures > 500 °C led to changes in the morphology of the LPSO structures. On one hand, the network-like structure dissolved while, on the other hand, both rodlike and blocky LPSO phases precipitated predominantly at the grain boundaries of the α-Mg matrix. This process was fostered by high temperatures and long holding times.

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Correlation of digital twin and roll surface sensor results for AZ31 alloy TRC process

Kwiecień,

Weiner,

Lypchanskyi

et al. 2024

J Mater Sci

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Due to the growing interest in lightweight constructions, the continuous casting of nonferrous metals is continuously developing as a result of the cost-effectiveness of this process, which combines several stages of sheet production. Unfortunately, because of the characteristics of the process, the parameters in the roll gap, such as, for example, pressure and temperature, are unknown, significantly affects the understanding of the phenomena occurring in the material during rolling. Therefore, at IMF Freiberg, a sensor consisting of a piezo sensor and two thermocouples measuring the temperature at two different heights was mounted on the surface of the roll, making it possible to control the process parameters live during the TRC trial. The measurements were further supported by a digital twin in the form of a layer model, combining a viscous and solid region for each layer in a single tool. The computations in this tool are performed offline and the computation time is in the order of seconds, thus much less than that of the finite element method. Because the layer model measures the temperature of the magnesium strip, FEM simulations were used to validate measurements from thermocouples. Experimental results have been obtained that allow for a direct correlation between the development of the pressure and temperature and the length of the fully solidified LD part in the roll gap zone, which correlates directly with the effective total equivalent strain. Using the sensor and layer model, it is possible to train a digital twin that can be used for online estimation of the final strip properties obtained in the TRC process. Graphical abstract

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Dynamic recrystallization behaviour of Twin Roll Cast ZAX210 strips during hot deformation

Cited by 4 publications

References 0 publications

Microstructural and Textural Investigation of an Mg-Zn-Al-Ca Alloy after Hot Plane Strain Compression

Microstructural and Textural Investigation of an Mg-Zn-Al-Ca Alloy after Hot Plane Strain Compression

Microstructure and Texture Evolution during Twin-Roll Casting and Annealing of a Mg–6.8Y2.5Zn–0.4Zr Alloy (WZ73)

Correlation of digital twin and roll surface sensor results for AZ31 alloy TRC process

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