Melt Conditioned Twin Roll Casting (MC-TRC) of Thin Mg-Alloy Strips for Direct Stamping of Mg Components

2013 ◽  
Vol 765 ◽  
pp. 170-174 ◽  
Author(s):  
Sanjeev Das ◽  
Shou Xun Ji ◽  
Omer El Fakir ◽  
Li Liang Wang ◽  
John P. Dear ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Hot Stamping ◽  
Az31 Alloy ◽  
Grain Structure ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Thin Walled ◽  
Twin Roll Cast ◽  
Twin Roll

In this paper we introduce a novel process for the production of thin-walled magnesium components by direct stamping of twin roll cast thin Mg strips. In this process, the melt conditioned twin roll casting (MC-TRC) process is used to produce thin Mg strips (thickness <2 mm) which have a fine equiaxed grain structure and little basal texture and, more importantly, are free from centreline segregation. Such thin Mg strips can be used for thin-walled component production by direct stamping without any rolling. A major advantage of this process is that it circumvents the low formability problem inherently associated with Mg based alloys. In this paper, AZ31 alloy is used to demonstrate this new process. For both TRC and MC-TRC strips, we will analyze the microstructures, assess the mechanical performance at elevated temperatures and conduct hot stamping in the as-cast condition without any prior rolling.

scholarly journals New Twin-Roll Cast Al-Li Based Alloys for High-Strength Applications

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 987
Author(s):  
Olexandr Grydin ◽  
Mykhailo Stolbchenko ◽  
Mirko Schaper ◽  
Sára Belejová ◽  
Rostislav Králík ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Light And Electron Microscopy ◽  
High Strength ◽  
Downstream Processing ◽  
Direct Chill ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Fine Grained Structure ◽  
Twin Roll Cast ◽  
Twin Roll

Al-Li based alloys are attractive materials for the aerospace industry. The twin-roll casting of such materials could provide properties not achievable by conventional direct-chill casting and downstream processing methods due to significantly higher solidification rates. An Al-Li-Cu-Mg-Zr alloy was twin-roll cast with the same alloy containing a small addition of Sc. The microstructure of as-cast materials and the influence of Sc on the behavior of the alloy at elevated temperatures were studied by means of light and electron microscopy and by resistivity measurements. A fine-grained structure was formed during twin-roll casting, but several surface and internal defects were found on the strips, which should be suppressed by a further adjustment of the casting conditions. The addition of Sc had a positive effect on grain size uniformity and microstructure stabilization at elevated temperatures, as shown by the precipitation of a fine dispersion of coherent Sc- and Zr-containing precipitates.

Solidification Mechanism of the Melt Conditioned Twin Roll Cast Magnesium Alloy

2014 ◽  
Vol 790-791 ◽  
pp. 291-295 ◽  
Author(s):  
Sanjeev Das ◽  
Nilam S. Barekar ◽  
Zhong Yun Fan
Keyword(s):  
Az31 Alloy ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Columnar Grains ◽  
Cast Magnesium ◽  
Twin Roll Cast ◽  
Solidification Mechanism ◽  
Twin Roll ◽  
Strength And Ductility

Twin roll casting (TRC) has been demonstrated to be a process capable of producing Mg sheets at a significantly reduced cost. However, the quality of the Mg sheets produced by the TRC process is limited due to the formation of coarse columnar grains and severe centreline segregation, which reduces both the strength and ductility of Mg-alloys. In this paper, melt conditioned (MC) has been employed prior to twin roll casting (TRC) of AZ31 alloy to understand its effect on the solidification mechanism. For comparison, AZ31 alloy strips were also produced through conventional TRC process. The results showed that the solidification mechanism can be completely altered by introducing MC in TRC process.

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 A Novel Approach to Improve the Microstructure and Mechanical Properties of Al–Mg–Si Aluminum Alloys during Twin-Roll Casting

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1713 ◽  
Author(s):  
Yong Li ◽  
Chen He ◽  
Jiadong Li ◽  
Zhaodong Wang ◽  
Di Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Crystallization Front ◽  
Alloying Elements ◽  
Cast Slab ◽  
Energy Dispersion Spectroscopy ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll Cast ◽  
Twin Roll

The main purpose of this present study was to investigate the different processing conditions on the microstructure, segregation behavior of alloying elements, and mechanical properties of Al−Mg−Si alloy twin-roll cast slab prepared using a novel twin-roll casting technology. The simulation of temperature field, distribution of alloying elements, tensile properties, hardness, and conductivity were examined by a Leica optical microscope, scanning electron microscopy, energy dispersion spectroscopy, electron probe microanalysis, and tensile tests. The results indicated that when the traditional twin-roll casting method was used to produce aluminum alloy strip, there are obvious centerline segregation defects due to the deep crystallization front depth and symmetrical solidification characteristics. When the forced-cooling technology was applied in the twin-roll casting process, by virtue of the changing of crystallization front depth and crystallization front shape, the segregation defects are obviously suppressed. Suggesting that this method can significantly improve the uniformity of alloying elements in the thickness direction of the twin-roll cast slab, ultimately improve the mechanical properties of AA6022 aluminum alloy.

Influence Research of Al and Zn Addition for Twin Roll Casting Magnesium During Multi-Pass Hot Rolling

2020 ◽  
Vol 12 (5) ◽  
pp. 685-692 ◽  
Author(s):  
Jia Yao ◽  
Min Zha ◽  
Huiyuan Wang ◽  
Wei Lu
Keyword(s):  
Hot Rolling ◽  
Texture Evolution ◽  
Az31 Alloy ◽  
Thickness Reduction ◽  
Twin Roll Casting ◽  
Texture Intensity ◽  
Pinning Effect ◽  
Roll Casting ◽  
Zn Addition ◽  
Twin Roll

This study was aimed at revealing the influence of Al and Zn additions on microstructure, texture evolution and mechanical properties of twin roll casting Mg during multi-pass hot rolling. Firstly, both pure Mg and AZ31 sheets were rolled 9 passes with ∼80% thickness reduction. More effective grain refinement in AZ31 compared to pure Mg after hot rolling, which caused by the pinning effect from fine Mg17Al12 particles present in AZ31 alloy. Meanwhile a strong basal texture gradually formed with increasing thickness reduction in pure Mg. With Al and Zn adding, the texture intensity of AZ31 was much lower than pure Mg in each rolling-pass. The 5th AZ31 sample features a maximum intensity of ∼12.9, which is reduced by 50.6% as compared to the value of ∼26.1 for pure Mg. Compared to pure Mg, the Al and Zn solutes and weakened texture in AZ31 favor the strong work hardening, which promotes a simultaneous high ultimate tensile strength of ∼270 MPa and ductility of ∼22% in the 5th AZ31 sample. The results will be helpful for the TRCed Mg alloys with huge potential for industrial application.

Deformation Behaviour of AZ31 Magnesium Alloy Sheets Produced by Twin-Roll Casting and Sequential Hot Rolling

2011 ◽  
Vol 299-300 ◽  
pp. 368-371 ◽  
Author(s):  
Yan Dong Yu ◽  
Peng Jiang ◽  
Chao Li ◽  
Kai Lin
Keyword(s):  
Strain Rate ◽  
Hot Rolling ◽  
Az31 Alloy ◽  
Grain Boundary Sliding ◽  
Uniaxial Tensile ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Deformation Properties ◽  
Increasing Temperature ◽  
Twin Roll

AZ31 alloy sheets were produced by twin-roll casting (TRC) and sequential hot rolling. Uniaxial tensile tests were used to evaluate the deformation properties of the AZ31 alloy at a strain rate of 7×10-4s-1 and a temperature range from room temperature to 400°C. The microstructure evolution and fracture behaviour were observed by optical microscopy and scanning electronic microscope. The results show that the elongation of the AZ31 alloy increases with increasing temperature at a strain rate of 7×10-4s-1. The AZ31 alloy begins to exhibit superplasticity at 300°C. The elongation of 497.8% is achieved at 400°C. The deformation of the AZ31 alloy at low temperature is controlled by dislocation motion, and with increasing temperature (above 300°C), grain boundary sliding (GBS) begins to play a dominant role during superplastic deformation.

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.

scholarly journals Effect of melt conditioning on heat treatment and mechanical properties of AZ31 alloy strips produced by twin roll casting

2015 ◽  
Vol 620 ◽  
pp. 223-232 ◽  
Author(s):  
Sanjeev Das ◽  
N.S. Barekar ◽  
Omer El Fakir ◽  
Liliang Wang ◽  
A.K. Prasada Rao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Az31 Alloy ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll

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

Application of Vertical-Type High-Speed Twin-Roll Casting for Up-Grade Recycling and Clad Sheets Fabrication of Aluminum Alloys

2016 ◽  
Vol 877 ◽  
pp. 56-61 ◽  
Author(s):  
Shinji Kumai ◽  
Yusuke Takayama ◽  
Ryoji Nakamura ◽  
Daisuke Shimosaka ◽  
Yohei Harada ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
High Speed ◽  
Cast Aluminum Alloy ◽  
Cast Aluminum ◽  
Casting Method ◽  
Twin Roll Casting ◽  
Roll Casting ◽  
Twin Roll Cast ◽  
Twin Roll

A horizontal-type twin roll casting method has been popular for producing aluminum alloy strips, however, it is characterized by a relatively low productivity (1~6 m/min). In contrast, a vertical-type high-speed twin-roll casting method possesses an extremely high productivity (60~120 m/min (1~2 m/s)) and an excellent heat extraction ability. The rapid cooling effect provided significant microstructure refinement and mechanical properties improvement in various kinds of cast aluminum alloy products. Not only “product to product recycling” but also “up-grade recycling” can be achieved by making good use of these merits. Two examples of application showing the potential of vertical-type high-speed twin roll casting method are presented. (1) Several kinds of Al-Si base alloy were cast into the strips. Not only strength and toughness but also formability was increased in the twin roll cast products. In particular, great improvement in deformability shows the potential of the twin-roll cast aluminum alloy products as substitutes for some wrought aluminum alloy products. (2) The vertical-type tandem twin-roll caster was able to fabricate a clad strip by single step. The A4045/A3003/A4045 aluminum alloy clad sheets produced by the twin-roll casting showed better mechanical properties than the conventional hot-roll bonded clad sheets.

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