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

Author(s):  
Petr Homola ◽  
Margarita Slámová ◽  
Miroslav Karlík ◽  
Jakub Čížek ◽  
Ivan Procházka
2004 ◽  
Vol 378 (1-2) ◽  
pp. 322-325 ◽  
Author(s):  
M. Karlı́k ◽  
P. Homola ◽  
M. Slámová

2006 ◽  
Vol 503-504 ◽  
pp. 281-286 ◽  
Author(s):  
Petr Homola ◽  
Margarita Slámová ◽  
Miroslav Karlík ◽  
Jakub Čížek ◽  
Ivan Procházka

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.


Author(s):  
Petr Homola ◽  
Margarita Slámovᆠ◽  
Peter Sláma ◽  
Miroslav Cieslar ◽  
Miroslav Karlík

2020 ◽  
Vol 326 ◽  
pp. 05003
Author(s):  
Miroslav Karlík ◽  
Petr Homola ◽  
Peter Sláma ◽  
Jiří Čapek ◽  
Petr Harcuba

Unhomogenized and homogenized AA8006 (Al-Fe-Mn-Si) alloy sheets twin-roll cast to strip 8.5 mm thick, processed by accumulative roll-bonding (ARB) on 2 mm thick sheets up to 6 cycles were studied. The microstructure was characterized by means of scanning and transmission electron microscopy and electron backscattered diffraction (EBSD), mechanical properties were monitored by hardness measurements and tensile tests. The macroscopic texture was determined by X-ray diffraction. The initial texture of the unhomogenized sheet is rotated cubic {001}<110> combined with recrystallization R texture {011}<211>, while the homogenized sheet has a cubic texture {001}<100> with remaining rolling component C {112}<111>. One ARB cycle leads to the formation of low-angle grain boundaries (LAGB) in original coarser grains and to a low angle rotation of the subgrains bounded by LAGB. After the 3rd and 6th ARB cycle unhomogenized and homogenized sheets show a common rolling texture of cold-rolled aluminium. The thermal stability of sheets processed by 6 ARB cycles was tested by isochronal annealing for 30 min up to 450°C. The homogenized sheet starts to recrystallize at 250°C, while the fine grain structure of the unhomogenized sheet is thermally stable up to 400°C.


2020 ◽  
Vol 168 ◽  
pp. 110536
Author(s):  
Zhen Xu ◽  
Xinyu Zhang ◽  
Hongbin Wang ◽  
Anni Gao ◽  
Tingyue Ma ◽  
...  

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