Formation of nanophases in a Cu–Zn alloy under high current density electropulsing

2000 ◽  
Vol 15 (10) ◽  
pp. 2065-2068 ◽  
Author(s):  
W. Zhang ◽  
M. L. Sui ◽  
K. Y. Hu ◽  
D. X. Li ◽  
X. N. Guo ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Energy ◽  
Coarse Grained ◽  
High Current ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Before And After ◽  
Electropulsing Treatment ◽  
Zn Alloy

The microstructure of samples before and after a high current density electropulsing treatment was characterized by using high-resolution transmission electron microscopy. It has been found that in the coarse-grained Cu–Zn alloy subjected to the electropulsing treatment, two nanophases were formed, α–Cu(Zn) and β′–(CuZn), the average grain size of which is about 11 nm. A possible mechanism for the formation of nanophases was proposed. The experimental results indicated that electropulsing, as an instantaneous high-energy input, plays an important role in the nonequilibrium microstructural changes in materials and serves as a potential processing approach to synthesize nanostructured materials.

Formation of a Nanostructure in a Low-carbon Steel Under High Current Density Electropulsing

2002 ◽  
Vol 17 (5) ◽  
pp. 921-924 ◽  
Author(s):  
Yizhou Zhou ◽  
Wei Zhang ◽  
Manling Sui ◽  
Douxing Li ◽  
Guanhu He ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Current Density ◽  
High Current Density ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
High Current ◽  
Low Carbon ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Electropulsing Treatment

The microstructure of a low-carbon steel after high current density electropulsing treatment was characterized by high-resolution transmission electron microscopy. It was found that nanostructured γ-Fe could be formed in the coarse-grained steel after the electropulsing treatment. The mechanism of the formation of a nanostructure was discussed. It was thought that change of the thermodynamic barrier during phase transformation under electropulsing was a factor that cannot be neglected. It was reasonable to anticipate that a new method might be developed to produce nanostructured materials directly from the conventional coarse-grained crystalline materials by applying high current density electropulsing.

Changes in Mechanical and Microstructural Properties of Magnesium Alloys Resulting from Superimposed High Current Density Pulses

2021 ◽  
Vol 1016 ◽  
pp. 385-391
Author(s):  
Eugen Demler ◽  
Alexander Diedrich ◽  
Andrej Dalinger ◽  
Gregory Gerstein ◽  
Sebastian Herbst ◽  
...  
Keyword(s):  
Magnesium Alloys ◽  
Current Density ◽  
High Current Density ◽  
Sheet Material ◽  
Compressive Load ◽  
Underlying Mechanism ◽  
Coarse Grained ◽  
High Current ◽  
Mechanical And Microstructural Properties ◽  
The Impact

Magnesium alloys are important engineering materials due to their good combination of strength and very low densities. However, the low ductility imposed by the hcp-lattice has thus far limited the application of magnesium alloys as sheet material. The use of the electroplastic effect offers a route to increase formability of magnesium alloys while being more energy efficient than conventional hot forming. The underlying mechanism (s) of this effect have not yet been fully understood. This study investigates the impact of high current density electrical pulses on magnesium alloys. Special consideration was given to the effect of the orientation of the applied electric current relative to the mechanical loading of the specimens. The results show that the mechanical properties of coarse-grained materials are more strongly affected by the current pulses than finer grained material. Applying the current parallel to the compressive load shows a more pronounced softening of the material than pulses applied perpendicular to the mechanical stress. Microstructure investigations revealed the formation of twinning solely in the interior of grains even at stresses below the yield point for both configurations.

scholarly journals Lithium Metal Anode for High-Power and High-Capacity Rechargeable Batteries

2021 ◽  
Vol 03 (02) ◽  
pp. 1-1
Author(s):  
Nobuyuki Imanishi ◽  
◽  
Daisuke Mori ◽  
Sou Taminato ◽  
Yasuo Takeda ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Specific Capacity ◽  
High Capacity ◽  
High Energy ◽  
Rechargeable Batteries ◽  
High Energy Density ◽  
Current Status ◽  
High Current ◽  
Lithium Metal

Because lithium metal exhibits high specific capacity and low potential, it is the best candidate for fabricating anodes for batteries. Rechargeable batteries fabricated using lithium anode exhibit high capacity and high potential cathode; these can be potentially used to fabricate high energy density batteries (>500 Wh kg–1) that can be used for the development of next-generation electric vehicles. However, the formation and growth of lithium dendrites and the low coulombic efficiency recorded during lithium plating and stripping under conditions of high current density hinder the use of lithium metal as the anodic material for the development of practical rechargeable batteries. In this short review, we outline the current status and prospects of lithium anodes for fabricating batteries in the presence of non-aqueous liquid, polymer, and solid electrolytes operated under conditions of high current density.

Ultrafine-grained microstructure in a Cu–Zn alloy produced by electropulsing treatment

2003 ◽  
Vol 18 (8) ◽  
pp. 1991-1997 ◽  
Author(s):  
Yizhou Zhou ◽  
Wei Zhang ◽  
Baoquan Wang ◽  
Jingdong Guo
Keyword(s):  
High Current Density ◽  
Coarse Grained ◽  
Heating And Cooling ◽  
Β Phase ◽  
Α Phase ◽  
Ultrafine Grained ◽  
Solid State Phase Transformation ◽  
Two Phases ◽  
Electropulsing Treatment ◽  
Zn Alloy

High-current-density electropulsing was applied to a coarse-grained Cu–Zn alloy with two phases of α-phase and β′-phase. It was found that with an electropulsing treatment, ultrafine-grained (UFG) microstructure could be formed in the α-phase, but could not be formed in the β-phase. The results indicated that the formation of UFG microstructure was dependent on solid-state phase transformation. The main reason for the formation of UFG microstructure by electropulsing treatment resulted from the effect of a decrease in thermodynamic barrier and enhancement of nucleation rate in a current-carrying system, but not from the high heating and cooling rate during electropulsing treatment. The bulk UFG samples prepared by electropulsing treatment were free of porosity and contamination and had no large microstrain. It was reasonable to anticipate that a new method might be developed to produce ideal bulk UFG samples directly from the conventional coarse-grained materials by application of electropulsing.

Analysis of Geometrical Design Parameters for High-Energy and High-Current-Density Pseudospark-Sourced Electron Beam Emission

2017 ◽  
Vol 64 (6) ◽  
pp. 2688-2693 ◽  
Author(s):  
Niraj Kumar ◽  
Dharmendra Kumar Pal ◽  
Ram Prakash Lamba ◽  
Udit Narayan Pal ◽  
Ram Prakash
Keyword(s):  
Electron Beam ◽  
Current Density ◽  
High Current Density ◽  
High Energy ◽  
Design Parameters ◽  
High Current ◽  
Geometrical Design
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