scholarly journals The INFLUENCE OF THE HOT-ROLLING TECHNIQUE FOR EN AW-8021B ALUMINIUM ALLOY ON THE MICROSTRUCTURAL PROPERTIES OF A COLD-ROLLED FOIL

2021 ◽  
Vol 55 (6) ◽  
Author(s):  
Jakob Kraner ◽  
Tomaž Smolar ◽  
Darja Volšak ◽  
Marjana Lažeta ◽  
Robert Skrbinek ◽  
...  

In the whole manufacturing chain of aluminium products, hot rolling significantly impacts the obtaining of favourable microstructures and desired mechanical properties of final products. The determination of crucial differences between the reverse hot rolling on a single-stand mill and the tandem hot rolling on a tandem-stand mill presented a major challenge. Besides the grain-size distribution in the microstructure’s cross-section, the crystallographic textures of hot-rolled strips were also determined and compared. The alternating band areas of a coarse-grained microstructure and fine-grained microstructure due to reverse hot rolling and, especially, the appearance of extremely fine grains on the surfaces present limitations compared to the tandem hot rolling. For subsequently cold-rolled foils, classical mechanical properties were measured. Besides, the usefulness of EN AW-8021B foils with a thickness of 60 µm for pharmaceutical-packaging applications was tested with a burst test. A minor but important difference of 1 % in the elongation is shown for the convex height increased by 1 mm.

2007 ◽  
Vol 546-549 ◽  
pp. 379-382
Author(s):  
Guang Jie Huang ◽  
Ling Yun Wang ◽  
Guang Sheng Huang ◽  
Fu Sheng Pan ◽  
Qing Liu

Microstructural evolution and mechanical properties of the AZ31 magnesium alloy during rolling and annealing process were investigated. The sheet samples were prepared after different stages of the hot rolling, cold rolling and annealing processes. The hot rolling temperature was between 300-450C and the final thickness of the cold rolled sheets was 1.5mm. The cold rolled sheets were annealed at different annealing temperature (260-350C) for different time (10~120min). Tensile test was performed to investigate the mechanical properties of the samples obtained from different stages. With aid of the optical microscopy, scanning electron microscopy (SEM) techniques, the microstructure of the samples were characterized and the results were related to the mechanical properties. It was found the hot-rolled sheets exhibit higher ductility comparing with the cold-rolled sheets. The microstructural investigation showed that the microstructure of the hot-rolled samples was dominated by recrystallized equiaxed grains while the microstructure of the cold-rolled samples dominated by deformation twining. By applying annealing on the cold-rolled sheets, fine recrystallization grains were obtained and ductility of the samples was improved. The effects of the grain size and twining on mechanical properties of the AZ31 sheet were further discussed based on the experimental results.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Qiang Wu ◽  
Kunning Fu ◽  
Ruizhi Wu ◽  
Jinghuai Zhang ◽  
Legan Hou ◽  
...  

The as-cast Mg-14Li-1Zn alloy was hot rolled at different temperatures with the reduction of 50%, followed by cold rolling with the reduction of 80%. The effects of the hot rolling temperature on the microstructure and mechanical properties of the final specimens were investigated. The results show that the higher rolling temperature brings about a more homogeneous microstructure, which is favorable for the subsequent cold rolling. When the hot rolling temperature is 300°C, the final specimen possesses the highest tensile strength and hardness of 238 MPa and 67.7 HV, respectively. When the hot rolling temperature is 200°C, the final specimen possesses the highest elongation of 24.6%.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 476
Author(s):  
Sayed Amer ◽  
Ruslan Barkov ◽  
Andrey Pozdniakov

Microstructure of Al-Cu-Yb and Al-Cu-Gd alloys at casting, hot-rolled -cold-rolled and annealed state were observed; the effect of annealing on the microstructure was studied, as were the mechanical properties and forming properties of the alloys, and the mechanism of action was explored. Analysis of the solidification process showed that the primary Al solidification is followed by the eutectic reaction. The second Al8Cu4Yb and Al8Cu4Gd phases play an important role as recrystallization inhibitor. The Al3Yb or (Al, Cu)17Yb2 phase inclusions are present in the Al-Cu-Yb alloy at the boundary between the eutectic and aluminum dendrites. The recrystallization starting temperature of the alloys is in the range of 250–350 °C after rolling with previous quenching at 590 and 605 °C for Al-Cu-Yb and Al-Cu-Gd, respectively. The hardness and tensile properties of Al-Cu-Yb and Al-Cu-Gd as-rolled alloys are reduced by increasing the annealing temperature and time. The as-rolled alloys have high mechanical properties: YS = 303 MPa, UTS = 327 MPa and El. = 3.2% for Al-Cu-Yb alloy, while YS = 290 MPa, UTS = 315 MPa and El. = 2.1% for Al-Cu-Gd alloy.


Hydrocarbon gels contain a number of materials, such as rubber, greases, saponified mineral oils, etc., of great interest for various engineering purposes. Specific requirements in mechanical properties have been met by producing gels in appropriately chosen patterns of constituent components of visible, colloidal, molecular and atomic sizes, ranging from coarse-grained aggregates, represented by sponges, foams, emulsions, etc.; to fine-grained and apparently homogeneous ones, represented by optically clear compounds. The engineer who has to deal with the whole range of such materials will adopt a macroscopic point of view, based on an apparent continuity of all the material structures and of the distributions in space and time of the displacements and forces occurring under mechanical actions. It has been possible to determine these distributions in the framework of a comprehensive scheme in which the fundamental principles of the mechanics of continuous media provide the theoretical basis, and a testing instrument of new design, termed Rheogoniometer, the means of experimental measurement (Weissenberg 1931, 1934, 1946, 1947, 1948).


Author(s):  
Bhalchandra S. Pujari ◽  
Snehal Shekatkar

The ongoing pandemic of 2019-nCov (COVID-19) coronavirus has made reliable epidemiological modeling an urgent necessity. Unfortunately, most of the existing models are either too fine-grained to be efficient or too coarse-grained to be reliable. Here we propose a computationally efficient hybrid approach that uses SIR model for individual cities which are in turn coupled via empirical transportation networks that facilitate migration among them. The treatment presented here differs from existing models in two crucial ways: first, self-consistent determination of coupling parameters so as to maintain the populations of individual cities, and second, the incorporation of distance dependent temporal delays in migration. We apply our model to Indian aviation as well as railway networks taking into account populations of more than 300 cities. Our results project that through the domestic transportation, the significant population is poised to be exposed within 90 days of the onset of epidemic. Thus, serious supervision of domestic transport networks is warranted even after restricting international migration.


2019 ◽  
Vol 26 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Andrzej Pawlak ◽  
Patrycja E. Szymczyk ◽  
Tomasz Kurzynowski ◽  
Edward Chlebus

Purpose This paper aims to discuss the results of material tests conducted on specimens manufactured from AZ31 alloy powder by selective laser melting (SLM) technology. The manufactured specimens were then subjected to porosity assessment, microstructure analysis as well as to mechanical and corrosion tests. Design/methodology/approach SLM process was optimized using the design of experiments tools. Experiments aimed at selecting optimum process parameters were carried out in accordance with a five-level rotatable central composite design. Findings The porosity results showed very low values of <1 per cent, whereas mechanical properties were close to the values reported for the reference wrought AZ31 alloy in hot-rolled state. A fine-grained microstructure was observed with a large range of grain size, which enhanced the material’s mechanical properties. Corrosion characteristics of the SLM-manufactured material exceed those determined for the wrought material. Originality/value The results presented in this paper drive interest in magnesium alloys used in additive manufacturing processes. Low porosity, good mechanical properties, form of the microstructure and, most importantly, improved corrosion characteristics suggest that SLM provides great potential for the manufacture of ultralight structures, including resorbable metallic implants.


Metallurgist ◽  
2017 ◽  
Vol 60 (9-10) ◽  
pp. 930-936 ◽  
Author(s):  
A. V. Nishchik ◽  
I. G. Rodionova ◽  
O. N. Baklanova ◽  
A. V. Grishin ◽  
R. R. Adigamov ◽  
...  

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1380
Author(s):  
Sofia Papadopoulou ◽  
Athina Kontopoulou ◽  
Evangelos Gavalas ◽  
Spyros Papaefthymiou

During forming, thickness reduction and thermal treatment affect the recrystallization and evolution of the crystallographic texture of metallic materials. The present study focuses on the consequences of rolling reduction of a widespread aluminum alloy with numerous automotive, marine and general-purpose applications, namely Al 5182. Emphasis is laid on the crystallographic texture and mechanical properties on both hot and cold-rolled semi-final products. In particular, a 2.8 mm-thick hot-rolled product was examined in the as-received condition, while two cold-rolled sheets, one 1.33 mm and the other 0.214 mm thick, both originating from the 2.8 mm material, were examined in both as-received and annealed (350 °C for 1 h) conditions. Electron back-scatter diffraction indicated the presence of a large percentage of random texture as well as a weak recrystallization texture for the hot-rolled product, whereas in the case of cold rolling the evolution of β-fiber texture was noted. In addition, tensile tests showed that both the anisotropy as well as the mechanical properties of the cold-rolled properties improved after annealing, being comparable to hot-rolled ones.


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