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.

Study on Molten Zone in Twin-Roll Casting of Magnesium Alloy Strip

2013 ◽  
Vol 395-396 ◽  
pp. 209-213
Author(s):  
Zhi Pu Pei ◽  
Hong Yang Zhao ◽  
Xiao Dong Hu ◽  
Dong Ying Ju
Keyword(s):  
Magnesium Alloy ◽  
Molten Pool ◽  
Casting Process ◽  
Solidification Structure ◽  
Molten Zone ◽  
Deformation Bands ◽  
Twin Roll Casting ◽  
Structure Changes ◽  
Roll Casting ◽  
Twin Roll

Thermal flow finite element simulation was carried out to deeply understand the solidification and deformation phenomena of magnesium alloy in molten zone during twin-roll casting process. The results show that temperature near the nip of the rolls is about 680K based on current conditions, and there are two vortexes in the molten pool during casting, a peak formed at solidus. Due to the metal flows in molten pool and relative rotates of the rolls, temperature field of molten zone is different from normal casting, which will cause the solidification structure changes. An experiment by using a vertical type twin-roll caster was also conducted, and the amount of deformation bands at the joint line is larger than that at the two sides. Substructures can be found due to dynamic recrystallization during casting process.

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.

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