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.

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 Mechanism of Electromagnetic Field in the Sub-RapidSolidification of High-Strength Al-Cu-Li Alloy Produced by Twin-Roll Casting

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 952
Author(s):  
Shiju Li ◽  
Bowen Wei ◽  
Wei Yu ◽  
Chen He ◽  
Yong Li ◽  
...  
Keyword(s):  
Body Force ◽  
High Strength ◽  
Solidification Structure ◽  
Experimental Characterization ◽  
Alloy Plate ◽  
Twin Roll Casting ◽  
Comprehensive Properties ◽  
Roll Casting ◽  
Mold Casting ◽  
Twin Roll

In this work, a Al-Cu-Li alloy plate with outstanding mechanical properties was successfully prepared with electromagnetic twin-roll casting (TRC) technology. The microstructure of Al-Cu-Li alloy manufactured by conventional mold casting, TRC, and electromagnetic TRC was studied in detail. The action mechanism of electromagnetic oscillation field (EOF) in the TRC process was studied by systematic experimental characterization and numerical simulation. The results show that the EOF will enlarge the circumfluence area in the cast-rolling zone, accelerate the mass transfer and heat transfer in the molten pool, and make the solute field and flow field in the liquid cavity tend to be evenly distributed. Further, the introduction of the EOF will produce the electromagnetic body force F with the maximum strength of 14 N/m3. The F acting on the solidification front will eliminate the accumulation and deposition of Cu2+, Li+, Mg2+, Zn2+, Mn2+ at the dendrite tip and inhibit the growth of dendrites. At the same time, the F can refine the microstructure of the TRC plate, promote the formation of equiaxed crystals, improve the supersaturated solid solubility of solute elements in the a(Al) matrix, and avoid the appearance of obvious solute segregation area or the formation of excessive solute enrichment area. Therefore, the macro-segregation in TRC plate was significantly reduced, the solidification structure was dramatically refined, and the comprehensive properties of the alloy were remarkably improved.

Effect of Processing Parameters on Microstructure and Properties of Continuously Cast Al-Mg Sheets

2005 ◽  
Vol 482 ◽  
pp. 279-282 ◽  
Author(s):  
Margarita Slámová ◽  
P. Sláma ◽  
Petr Homola ◽  
Miroslav Karlík
Keyword(s):  
High Strength ◽  
Cost Effective ◽  
Processing Parameters ◽  
Direct Chill ◽  
Continuously Cast ◽  
Chill Cast ◽  
Direct Chill Cast ◽  
Twin Roll Cast ◽  
Twin Roll ◽  
Al Mg Alloys

Inner panels of modern ecological cars are nowadays manufactured from Al-Mg alloys. Continuously twin-roll cast sheets are a cost effective substitution for direct-chill cast sheets. The effect of composition and down-stream processing on sheet properties should be well understood in order to produce high quality products, which exhibit good formability and high strength. Finegrained microstructure and well-balanced texture are the necessary pre-requisites. Results of the investigation of twin-roll cast AlMg2Mn0.8 and AlMg3 alloys are reported. Sheets of 1.0 mm gauge were prepared using different processing routes. The route involving homogenisation results in grain coarsening and anisotropy, however, deep-drawing ability is affected only a little.

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.

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.

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