Interface Characterization of Al-Cu Micro-Laminates Fabricated by Electrically-Assisted Roll Bonding

2016 ◽  
Author(s):  
Marzyeh Moradi ◽  
Man-Kwan Ng ◽  
Taekyung Lee ◽  
Jian Cao ◽  
Yoosuf N. Picard
Keyword(s):  
High Current Density ◽  
Strong Dependence ◽  
Electrical Current ◽  
Simultaneous Application ◽  
Roll Bonding ◽  
Electrically Assisted ◽  
Micro Cracks ◽  
Interface Characteristics ◽  
Peel Tests

Interface characteristics of Al/Cu micro-laminates fabricated by an Electrically-Assisted Roll Bonding (EARB) process were studied to understand the underlying physical/chemical phenomena that lead to bond strength enhancement when applying electrical current during deformation. Peel tests were conducted for the Al/Cu roll-bonded laminates produced with no current and under 50A and 150A applied current. After peel tests using a micro-tensile machine, the fractured surfaces of both the Al and Cu–sides were examined using scanning electron microscopy (SEM) for fractography and SEM-based energy dispersive (EDS) analysis. Results revealed the strong dependence of the fracture path and its morphology on the strength of the bond, which is influenced by various phenomena occurring at the interface during EARB, such as microextrusion through surface micro-cracks, possible formation of intermetallic components and thermal softening during simultaneous application of strain and high current density.

Interface Characterization of Al–Cu Microlaminates Fabricated By Electrically Assisted Roll Bonding

2017 ◽  
Vol 5 (3) ◽  
Author(s):  
Marzyeh Moradi ◽  
Man-Kwan Ng ◽  
Taekyung Lee ◽  
Jian Cao ◽  
Yoosuf N. Picard
Keyword(s):  
High Current Density ◽  
Strong Dependence ◽  
Electrical Current ◽  
Applied Current ◽  
Simultaneous Application ◽  
Roll Bonding ◽  
Electrically Assisted ◽  
Interface Characteristics ◽  
Peel Tests

Interface characteristics of Al/Cu microlaminates fabricated by an electrically assisted roll bonding (EARB) process were studied to understand the underlying physical/chemical phenomena that lead to bond strength enhancement when applying electrical current during deformation. Peel tests were conducted for the Al/Cu roll-bonded laminates produced under 0 A, 50 A, and 150 A applied current. After peel tests using a microtensile machine, the fractured surfaces of both the Al and Cu–sides were examined using scanning electron microscopy (SEM) for fractography and SEM-based energy dispersive (EDS) analysis. Results revealed the strong dependence of the fracture path and its morphology on the strength of the bond, which is influenced by various phenomena occurring at the interface during EARB, such as microextrusion through surface microcracks, possible formation of intermetallic components and thermal softening during simultaneous application of strain and high current density.

Thermal Response Characterization of Sheet Metals During Electrically-Assisted Forming (EAF)

2012 ◽  
Author(s):  
Joshua J. Jones ◽  
Laine Mears
Keyword(s):  
Joule Heating ◽  
Thermal Response ◽  
High Strength ◽  
Electrical Current ◽  
Deformation Model ◽  
Applied Current ◽  
Electrically Assisted ◽  
Lightweight Engineering ◽  
Deformation Tests

For the current practice of lightweight engineering in the automotive sector, it is common to introduce and use low density/high strength materials instead of costly engine/drivetrain technologies. With the introduction of these materials there are commonly many manufacturing difficulties which arise during their incorporation to the vehicle. As a result, new processes which improve the manufacturability of these materials are necessary. This work examines the manufacturing technique of Electrically-Assisted Forming (EAF) where an electrical current is applied to the workpiece during deformation. As a result of the applied current, Joule heating is present which increases the temperature of the material. In this work the thermal response of sheet metal for stationary and deformation tests using this process are explored and modeled. The results of the model show good agreement for the stationary tests while the deformation model predicts that all of the applied electrical current may not be transformed into Joule heating. Thus, this work suggests from the observed response that a portion of the applied current may be directly aiding in deformation (i.e. the Electroplastic Effect).

Fabrication and Analysis of Accumulative Roll Bonding Process between Magnesium and Aluminum Multi-Layers

2018 ◽  
Vol 877 ◽  
pp. 183-189 ◽  
Author(s):  
Muralimohan Cheepu ◽  
S. Haribabu ◽  
T. Ramachandraiah ◽  
B. Srinivas ◽  
Devuri Venkateswarulu ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Accumulative Roll Bonding ◽  
Dissimilar Materials ◽  
Roll Bonding ◽  
Micro Cracks ◽  
Interface Characteristics ◽  
Bonding Properties ◽  
Strength And Deformation ◽  
Solid State Joining ◽  
Joining Process

In the present study commercially pure magnesium and aluminum strips were fabricated using the process of accumulative roll bonding. It is a prominent solid state joining process to manufacture similar and dissimilar materials for various applications. Three layers of stack was used for bonding of multilayered composite and preheated at 250 °C for 20 min. The effects of rolling parameters on bond strength and deformation of the strips were analyzed. The interface between aluminum and magnesium were characterized to identify the formation of diffusion compounds, and are found to be the presence of Al12Mg17 intermetallic compounds. Tensile strength of the bonds was increased with the decreasing of thickness of the strips. The interface characteristics were analyzed using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDAX) to reveal the intermetallic compounds, micro cracks and bonding properties. The strength of the composites is varying with width of the intermediate strip and maximum strength values were obtained after three passes of the roll bonding.

CBED analysis of impurity distributions in AlN

1990 ◽  
Vol 48 (4) ◽  
pp. 214-215
Author(s):  
Daniel Callahan ◽  
G. Thomas
Keyword(s):  
Aluminum Nitride ◽  
Bulk Material ◽  
Strong Dependence ◽  
Lattice Parameter ◽  
Promising Technique ◽  
Nitride Ceramics ◽  
Surface Phases ◽  
Convergent Beam ◽  
Oxygen Impurities

Oxygen impurities may significantly influence the properties of nitride ceramics with a strong dependence on the microstructural distribution of the impurity. For example, amorphous oxygen-rich grain boundary phases are well-known to cause high-temperature mechanical strength degradation in silicon nitride whereas solutionized oxygen is known to decrease the thermal conductivity of aluminum nitride. Microanalytical characterization of these impurities by spectral methods in the AEM is complicated by reactions which form oxygen-rich surface phases not representative of the bulk material. Furthermore, the impurity concentrations found in higher quality ceramics may be too low to measure by EDS or PEELS. Consequently an alternate method for the characterization of impurities in these ceramics has been investigated.Convergent beam electron diffraction (CBED) is a promising technique for the study of impurity distributions in aluminum nitride ceramics. Oxygen is known to enter into stoichiometric solutions with AIN with a consequent decrease in lattice parameter.

scholarly journals Lamellar Polypyrene Based on Attapulgite–Sulfur Composite for Lithium–Sulfur Battery

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 483
Author(s):  
Jing Wang ◽  
Riwei Xu ◽  
Chengzhong Wang ◽  
Jinping Xiong
Keyword(s):  
Cathode Material ◽  
Current Density ◽  
High Current Density ◽  
Specific Capacity ◽  
Lithium Sulfur Batteries ◽  
Rate Test ◽  
Sulfur Battery ◽  
Lower Capacity ◽  
Lithium Sulfur

We report on the preparation and characterization of a novel lamellar polypyrrole using an attapulgite–sulfur composite as a hard template. Pretreated attapulgite was utilized as the carrier of elemental sulfur and the attapulgite–sulfur–polypyrrole (AT @400 °C–S–PPy) composite with 50 wt.% sulfur was obtained. The structure and morphology of the composite were characterized with infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). An AT @400 °C–S–PPy composite was further utilized as the cathode material for lithium–sulfur batteries. The first discharge specific capacity of this kind of battery reached 1175 mAh/g at a 0.1 C current rate and remained at 518 mAh/g after 100 cycles with capacity retention close to 44%. In the rate test, compared with the polypyrrole–sulfur (PPy–S) cathode material, the AT @400 °C–S–PPy cathode material showed lower capacity at a high current density, but it showed higher capacity when the current came back to a low current density, which was attributed to the “recycling” of pores and channels of attapulgite. Therefore, the lamellar composite with special pore structure has great value in improving the performance of lithium–sulfur batteries.

Electrochemical characterization of micro-cracks in polyurethane resin films deposited on metallic surfaces

2016 ◽  
Vol 46 (12) ◽  
pp. 1237-1243 ◽  
Author(s):  
Karun K. Rao ◽  
Molly Ferguson ◽  
Kyle Murphy ◽  
Jean Zhao ◽  
Daniel Lacks ◽  
...  
Keyword(s):  
Electrochemical Characterization ◽  
Metallic Surfaces ◽  
Polyurethane Resin ◽  
Micro Cracks

scholarly journals Bonding of similar AA3105 aluminum alloy by Accumulative Roll Bonding process

2021 ◽  
Author(s):  
Mohamad El Mehtedi ◽  
Daniele Lai ◽  
Rayane Almehtedi ◽  
Mauro Carta ◽  
Pasquale Buonadonna ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Accumulative Roll Bonding ◽  
Sheet Thickness ◽  
Tensile Tests ◽  
Ultrafine Grain ◽  
Reinforced Composites ◽  
Final Thickness ◽  
Roll Bonding ◽  
Dissimilar Metal ◽  
Micro Cracks

Accumulative roll-bonding (ARB) is a novel plastic straining process aimed at bonding of similar and dissimilar metal combinations. Moreover, it is used recently to produce ultrafine grain materials and metal matrix reinforced composites to enhance mechanical, electrical, and corrosion resistance properties. This work presents an experimental study of roll bonding and accumulative roll bonding of similar AA3105 aluminum alloy at 300°C with a final thickness of 1.2 mm, focusing especially on bond strength evaluation and layers continuities. Tensile tests and three-points bending were performed to mechanical characterize the produced sheets in the various steps and based on the number of the cycles. The maximum strength was reached after 3 ARB cycles. After 4 cycles, the bonding interfaces have a uniform distribution through the sheet thickness, it is possible to distinguish only the interface formed in the last pass in the fracture surface, and no significant enhancement in strength was observed. Starting from 2 ARB cycles, micro-cracks were observed at the outer surface for bending angles greater than 90 deg, and at 180 deg all ARBed samples except A1 were failed.

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