scholarly journals Hot Deformation Behavior and Microstructural Evolution of Twin-Roll-Casting Mg Alloy during High-Temperature Compression

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Qingshan Yang ◽  
Jiahong Dai ◽  
Sensen Chai ◽  
Daliang Yu ◽  
Bin Jiang ◽  
...  
Keyword(s):  
Grain Size ◽  
Flow Stress ◽  
Microstructural Evolution ◽  
Deformation Behavior ◽  
Volume Fraction ◽  
Mg Alloy ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Average Grain Size ◽  
Twin Roll

The deformation behavior and microstructural evolution of twin-roll-casting AZ31 Mg alloy sheets were investigated via hot compression tests at 0°, 5°, and 10° from the normal direction. Compression strains of 5%, 15%, 25%, and 35% were employed at high temperatures of 450°C and 500°C. The flow stress as well as the difference in the flow stress associated with different sampling directions decreased when the temperature was increased. Furthermore, the volume fraction of dynamically recrystallized grains increased with increasing deformation, whereas the average grain size decreased. The DRX grain size and the volume fraction of dynamically recrystallized grains increased with increasing deformation temperature. During ultrahigh temperature compression, the effect of sampling direction on the compression microstructure is relatively small.

Twin-Roll Cast Al-Clad Magnesium Alloy

2009 ◽  
Vol 618-619 ◽  
pp. 467-470 ◽  
Author(s):  
A.K. Prasada Rao ◽  
K.H. Kim ◽  
J.H. Bae ◽  
Geun Tae Bae ◽  
Dong Hyuk Shin ◽  
...  
Keyword(s):  
Reaction Zone ◽  
Transverse Section ◽  
Intermetallic Phases ◽  
Alloy Sheet ◽  
Mg Alloy ◽  
Microstructural Investigation ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll Cast ◽  
Twin Roll

An attempt has been made to clad Mg alloy with Al by twin-roll casting. This was done by inserting an Al sheet between the roll and the Mg alloy melt during twin-roll casting. Microstructural investigation across the transverse section of the as-cast Al-clad Mg alloy sheet reveals a very good interfacial bonding between Al and the base Mg alloy. Annealing of the Al-clad Mg alloy sheet results in the formation of layers of various intermetallic phases along the Mg/Al interface. Subsequent rolling of the as-annealed sheet significantly improves the formability of the reaction zone, as evidenced by the cracking of the base Mg alloy before the cracking of the reaction zone.

scholarly journals Effect of Cooling Rate on Microstructure and Properties of Twin-Roll Casting 6061 Aluminum Alloy Sheet

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1168 ◽  
Author(s):  
Zhen Xu ◽  
Sixue Wang ◽  
Hongbin Wang ◽  
Hua Song ◽  
Shengli Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Cooling Rate ◽  
Alloy Sheet ◽  
Aluminum Alloy Sheet ◽  
6061 Aluminum Alloy ◽  
Microstructure And Properties ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll

In this study, a twin-roll casting sheet of 6061 aluminum alloy was cooled using furnace, asbestos, air, wind and water. The effect of cooling rate on the microstructure and properties of twin-roll casting 6061 aluminum alloy sheet were studied. Optical microscope, scanning electron microscope, X-ray diffraction, microhardness tester and universal tensile machine were used to observe the microstructure and properties of twin-roll casting sheet of 6061 aluminum alloy. The results show that the higher the cooling rate, the smaller the grain size of the alloy and the smaller the number of precipitated phases in the matrix. Uniform grain size of the alloy could be obtained at a stable cooling rate. The hardness, tensile strength and elongation of the twin-roll casting sheet increased with cooling rate. Under wind cooling condition, the twin-roll casting sheet demonstrated excellent comprehensive performance, i.e., 88 MPa of yield strength, 178 MPa of tensile strength and 15% of elongation, respectively. A quantitative Hall–Petch relation was established to predict the yield strength of 6061 twin-roll casting sheets with different grain sizes and cooling rate.

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

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 513 ◽  
Author(s):  
Kristina Kittner ◽  
Madlen Ullmann ◽  
Falko Arndt ◽  
Rudolf Kawalla ◽  
Ulrich Prahl
Keyword(s):  
Grain Boundaries ◽  
High Temperatures ◽  
Texture Evolution ◽  
Cast State ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Twin Roll Cast ◽  
Twin Roll

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.

Solidification Microstructure and Mechanical Properties of Hot Rolled and Annealed Mg Sheet Produced through Twin Roll Casting Route

2011 ◽  
Vol 690 ◽  
pp. 331-334 ◽  
Author(s):  
M. Aljarrah ◽  
Elhachmi Essadiqi ◽  
D.H. Kang ◽  
In Ho Jung
Keyword(s):  
Mechanical Properties ◽  
Fuel Efficiency ◽  
Direct Chill ◽  
Alloy Sheet ◽  
Process Conditions ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Average Grain Size ◽  
Az31 Sheet ◽  
Twin Roll

The use of wrought magnesium for automobile structural components is an important component of the mass reduction strategy for automobiles to improve their fuel efficiency. Compared to Direct chill casting, Twin Roll Casting (TRC) allows major reduction of hot rolling steps in the production of Mg sheet due to the thin thickness of the as-cast strip. This TRC route can substantially reduce the time and cost to produce Mg alloy sheet product. In this work, AZ31 magnesium alloy was casted to 5 and 6 mm thick strips under different process conditions. Microstructure of these strips was analyzed using optical microscopy, SEM and EPMA. TRC strip was annealed under two different conditions: 2 hours at 330 and 1 hour at 400°C. It has been found that heat treatment at 400°C for 1 hour reduces centerline segregation significantly. TRC strips were rolled down to 2 mm and annealed at 450°C for 2 minutes. The average grain size was 4-6 µm and mechanical properties were comparable with commercial AZ31 sheet.

A New Analytical Model for the Flow Stress of Twin-roll Casting Magnesium Sheet at Elevated Temperatures

2010 ◽  
Vol 26 (5) ◽  
pp. 461-466 ◽  
Author(s):  
Zhimin Liu ◽  
Shuming Xing ◽  
Peiwei Bao ◽  
Nan Li ◽  
Shuqing Yao ◽  
...  
Keyword(s):  
Flow Stress ◽  
Analytical Model ◽  
Elevated Temperatures ◽  
Magnesium Sheet ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll

Microstructure Analysis and Bulk Texture Study in Wide Magnesium Alloy Sheets Processed by Twin-Roll Casting

2021 ◽  
Vol 13 (9) ◽  
pp. 1771-1780
Author(s):  
Yu-Qing Li ◽  
Tong Wang ◽  
Yun-Tao Liu ◽  
Dong-Feng Chen ◽  
Kai Sun ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Alloy Composition ◽  
Texture Evolution ◽  
Mg Alloy ◽  
Basal Texture ◽  
Twin Roll Casting ◽  
Electron Backscattering Diffraction ◽  
Roll Casting ◽  
Twin Roll ◽  
Zn Alloy

The wide magnesium (Mg) alloy sheets produced by twin-roll casting (TRC) are prone to have an inhomogeneous microstructure and basal texture. Texture has a significant effect on the properties of Mg alloy sheets for the processes after TRC, which can be greatly modified by alloy composition. However, systematic studies on the bulk texture of TRCed Mg alloy sheets using neutron diffraction are lacking. In this study, neutron diffraction was used to explore the bulk textures in different positions of the Mg, Mg–Al–Zn, and Mg–Al–Sn–Zn alloy sheets produced by TRC, besides microstructure and micro-texture analysis using field emission scanning electron microscopy and electron backscattering diffraction. The influence of alloy composition on the microstructure and texture evolution of TRCed Mg alloy sheets is explored and discussed. The TRCed pure Mg sheet possesses a relatively strong basal texture, and the texture distribution is inhomogeneous; while TRCed Mg–Al–Sn–Zn alloy sheets feature much weaker textures and a relatively homogenous distribution in different positions. The present study provides guidance for the control of texture via tailoring alloy compositions, which provides candidate Mg alloys suitable for the TRC process.

Microstructure and Tensile Properties of Al-(5~10)wt%Mg Alloy Sheets Fabricated by Twin Roll Casting and Rolling Process

2010 ◽  
Vol 443 ◽  
pp. 45-50 ◽  
Author(s):  
Hyoung Wook Kim ◽  
Jae Hyeng Cho ◽  
Cha Yong Lim ◽  
Suk Bong Kang
Keyword(s):  
Tensile Properties ◽  
Surface Quality ◽  
Intermetallic Particle ◽  
Process Condition ◽  
High Strength ◽  
Mg Alloy ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll

High strength Al-Mg alloy strips with high Mg contents (5-10wt%Mg) were successfully fabricated by twin roll casting. In order to get a good surface quality of Al-Mg strips, an optimum process condition was investigated in this experiment. The morphology of the cast nozzle and the roll separate force during twin roll casting was important to improve the surface quality of the strip and homogeneity of the cast structure through the thickness. The size of intermetallic particle like Al-Fe compounds was reduced down to 1~2m due to a high cooling rate of Al melt during strip casting. In addition, the dendrite structure was very fine and the segregation of Al8Mg5 phase between grains was remarkably reduced. Therefore, the Al-Mg strips have good workability during additional cold/warm rolling processes. After annealing, the rolled sheets have superior tensile properties to a commercial high strength Al-Mg alloy sheet.

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