scholarly journals Intermetallic Phases Identification and Diffusion Simulation in Twin-Roll Cast Al-Fe Clad Sheet

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7771
Author(s):  
Barbora Křivská ◽  
Michaela Šlapáková ◽  
Jozef Veselý ◽  
Martin Kihoulou ◽  
Klaudia Fekete ◽  
...  
Keyword(s):  
Interdiffusion Coefficient ◽  
Intermetallic Layer ◽  
Industrial Applications ◽  
Intermetallic Phases ◽  
Selective Area ◽  
Transmission Electron ◽  
Clad Sheet ◽  
Twin Roll Cast ◽  
Diffusion Simulation ◽  
Twin Roll

Aluminium steel clad materials have high potential for industrial applications. Their mechanical properties are governed by an intermetallic layer, which forms upon heat treatment at the Al-Fe interface. Transmission electron microscopy was employed to identify the phases present at the interface by selective area electron diffraction and energy dispersive spectroscopy. Three phases were identified: orthorhombic Al5Fe2, monoclinic Al13Fe4 and cubic Al19Fe4MnSi2. An effective interdiffusion coefficient dependent on concentration was determined according to the Boltzmann–Matano method. The highest value of the interdiffusion coefficient was reached at the composition of the intermetallic phases. Afterwards, the process of diffusion considering the evaluated interdiffusion coefficient was simulated using the finite element method. Results of the simulations revealed that growth of the intermetallic phases proceeds preferentially in the direction of aluminium.

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.

Static Recrystallization of Magnesium Alloy during TRC-HC Deformation Followed by Annealing

2011 ◽  
Vol 295-297 ◽  
pp. 730-733 ◽  
Author(s):  
Yong Wang ◽  
Shou Ren Wang ◽  
Ru Ma ◽  
Li Ying Yang
Keyword(s):  
Magnesium Alloy ◽  
Grain Boundary ◽  
Static Recrystallization ◽  
Electron Backscatter Diffraction ◽  
Boundary Migration ◽  
Transmission Electron ◽  
Subgrain Rotation ◽  
Twin Roll Cast ◽  
Backscatter Diffraction ◽  
Twin Roll

Using optical microscopy, electron backscatter diffraction and transmission electron microscopy, the static recrystallization (SRX) mechanisms of ZK 60 magnesium alloy was examined under twin-roll-cast and hot compression (TRC-HC, 350 °C/0.1 s-1) and subsequent annealing (1000 second at 250-400°C). The static recrystallization (SRX) mechanisms, such as grain boundary migration (GBM), grain boundary bulging (GLB) and subgrain rotation (SGR), were discussed.

Effect of the Temperature of Accumulative Roll Bonding on the Microstructure and Properties of Twin-Roll Cast AA8006 Alloy

2006 ◽  
Vol 503-504 ◽  
pp. 281-286 ◽  
Author(s):  
Petr Homola ◽  
Margarita Slámová ◽  
Miroslav Karlík ◽  
Jakub Čížek ◽  
Ivan Procházka
Keyword(s):  
Accumulative Roll Bonding ◽  
Positron Annihilation Spectroscopy ◽  
Tensile Tests ◽  
Special Equipment ◽  
Roll Bonding ◽  
Fine Grained ◽  
Transmission Electron ◽  
Number Of Cycles ◽  
Twin Roll Cast ◽  
Twin Roll

Accumulative Roll Bonding (ARB) does not require any special equipment and enables the production of large amounts of ultra-fine grained (UFG) materials. Grain refinement is thermally stable in materials with finely dispersed particles such as twin-roll cast (TRC) aluminium alloy sheets, favourable materials for manufacturing UFG sheets. The results of a study of the effect of ARB temperature on bonding quality, structure and properties of TRC AA8006 sheet are presented. Examinations by light and transmission electron microscopy, positron annihilation spectroscopy (PAS), hardness and tensile tests were used in the study. After two cycles at 200°C, mean grain size of 0.4 - 0.8 μm is achieved, but areas with extremely fine grains of 0.1 to 0.3 μm in diameter are also observed. Hardness increases significantly after two cycles and it rises a little in subsequent cycles. Processing at higher temperatures (up to 350°C) results in better bonding but it produces smaller increase in hardness. Significant increase of dislocation density is observed by PAS after the first cycle at 250°C but it does not continue during subsequent cycles. Partial recrystallization occurs in samples processed at temperatures above 250°C explaining the smaller increase in hardness. Softening level depends on both ARB temperature and number of cycles. The thermal stability of refined structures produced by ARB at 250°C is better than these formed at higher temperatures.

Accumulative Roll-Bonding (ARB) of Sheets of Aluminium and its Commercial Alloys AA8006 and AA5754 at Ambient and Elevated Temperatures

2007 ◽  
Vol 546-549 ◽  
pp. 767-774 ◽  
Author(s):  
Miroslav Karlík ◽  
Margarita Slámová ◽  
Petr Homola ◽  
P. Sláma ◽  
Miroslav Cieslar
Keyword(s):  
Elevated Temperatures ◽  
Large Fraction ◽  
True Strain ◽  
Grain Structure ◽  
Pure Aluminium ◽  
High Concentration ◽  
Fine Grain ◽  
Transmission Electron ◽  
Twin Roll Cast ◽  
Twin Roll

Mechanical properties and microstructure of twin-roll cast (TRC) pure aluminium, Al-Fe-Mn-Si (AA8006) and Al-Mg (AA5754) alloy sheets ARB processed at ambient and elevated temperatures (200, 250, 300 and 350°C) were investigated. Processing at elevated temperatures results in better bonding but it produces smaller increases in hardness. AA8006 specimens were processed without any problems up to 7 cycles. The alloy AA5754 suffered from severe edge and notch cracking since the first cycle. The strength was evaluated from tensile test and microhardness measurements; the microstructure was examined using light microscopy, and transmission electron microscopy. The microstructure was compared to that of conventionally cold rolled (CCR) specimens with true strain ε of 0.8, 1.6, 2.4 and 3.2 corresponding to the strain induced by 1 to 4 ARB cycles. The work hardening of alloy AA8006 saturated after the 3rd cycle, whereas the hardness of alloy AA5754 increased steadily up to the 5th cycle. Very fine grain structure with large fraction of high angle boundaries was observed in both alloys after two cycles of ARB. The grains were refined to submicrometre and nanometre size (down to 90 nm in alloy AA5754). Intensive post-dynamic recovery was observed in AA8006 specimens. The recovery is less pronounced in the AA5754 alloy with high concentration of solute atoms in solid solution.

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