Visualizing the Electron Wind Force in the Elastic Regime

Nano Letters ◽  
2021 ◽  
Author(s):  
Matthew Mecklenburg ◽  
Brian T. Zutter ◽  
Xin Yi Ling ◽  
William A. Hubbard ◽  
B. C. Regan
Keyword(s):  
Wind Force ◽  
Elastic Regime ◽  
Electron Wind

scholarly journals In Situ Visualization of the Electron Wind Force in the Elastic Regime

2021 ◽  
Vol 27 (S1) ◽  
pp. 106-107
Author(s):  
Matthew Mecklenburg ◽  
Brian Zutter ◽  
William A. Hubbard ◽  
Xin Yi Ling ◽  
B. C. Regan
Keyword(s):  
Wind Force ◽  
Elastic Regime ◽  
In Situ Visualization ◽  
Electron Wind

scholarly journals Static Recrystallization Microstructure Evolution in a Cold-Deformed Ni-Based Superalloy during Electropulsing Treatment

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 884
Author(s):  
Hongbin Zhang ◽  
Chengcai Zhang ◽  
Baokun Han ◽  
Kuidong Gao ◽  
Ruirui Fang ◽  
...  
Keyword(s):  
Grain Size ◽  
Thermal Effect ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
Heating Effect ◽  
Wind Force ◽  
Average Grain Size ◽  
Higher Temperature ◽  
Electropulsing Treatment ◽  
Electron Wind

The influence of electropulsing treatment (EPT) parameters on the static recrystallization (SRX) microstructure in a cold-deformed Ni-based superalloy was investigated. During EPT, both the volume fraction of SRX grains and the average grain size increased with the increasing EPT temperature, which was attributed to the thermal effect and athermal effect induced by EPT. The mobility of SRX grain boundaries was promoted at the higher temperature due to the thermal effect, while the nucleation rate would be increased by EPT through decreasing the thermodynamic barrier. The formation of parallel dislocations caused by electron wind force could also play an indirect role in promoting SRX process. Moreover, the volume fraction of SRX grains increased significantly with the extension of EPT time at 700 °C, while the EPT time had a trivial effect on the average grain size. In addition, the sufficient deformation was essential to the occurrence of SRX behavior during EPT, and the localized Joule heating effect could promote the SRX behavior in the samples with the larger strains. Besides that, the influence of twining and carbides on the SRX behaviors was also investigated.

Effect of Microstructure on Hot Bulging Deformation for AZ31 Magnesium Alloy Sheet with Resistance Heating

2014 ◽  
Vol 783-786 ◽  
pp. 537-540
Author(s):  
Kai Feng Zhang ◽  
Jing Yuan Liu ◽  
Chao Li
Keyword(s):  
Magnesium Alloy ◽  
Pulse Current ◽  
Alloy Sheet ◽  
Az31 Magnesium Alloy ◽  
Coarse Grained ◽  
Wind Force ◽  
Magnesium Alloy Sheet ◽  
Fine Grained ◽  
Az31 Magnesium Alloy Sheet ◽  
Electron Wind

To enhance the heating efficiency and the formability of AZ31 magnesium alloy, the assistance heating method is adopted during the hot bulging process. The free bulging test of coarse grained and fine grained AZ31 magnesium alloy sheet was carried out. During the forming process, the effects of pulse current on the formed sheet combine both thermoelectricity and electro-plasticity. Directional and asymmetrical deformation of the coarse-grained AZ31 magnesium alloy sheet by the effect of pulse current is observed and analyzed. But in the same processing condition, the deformation of fine grained AZ31 magnesium alloy sheet is symmetrical. To investigate the influence of electron wind force on pulse current auxiliary bulging process, the simulation of AZ31 magnesium alloy pulse current auxiliary bulging based on the electron wind force value calculated by mathematical model was performed using the Marc software. The bulging simulation result showed a special phenomenon that the shape of the bulging specimen is unsymmetrical and the dome deviated from the symmetry axis to the side of positive pole. The simulation results were basically consistent with the experimental results. The deformation properties, microstructure characteristics, dislocation movement of the AZ31 magnesium alloy during gas bulging processing by the pulse current are investigated.

scholarly journals The Effect of Grain Orientation of β-Sn on Copper Pillar Solder Joints during Electromigration

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 108
Author(s):  
Kexin Xu ◽  
Xing Fu ◽  
Xinjie Wang ◽  
Zhiwei Fu ◽  
Xiaofeng Yang ◽  
...  
Keyword(s):  
Electric Current ◽  
Grain Orientation ◽  
Solder Joints ◽  
Metal Dissolution ◽  
Wind Force ◽  
Electron Backscattered Diffraction ◽  
Combined Action ◽  
Free Solder ◽  
Electron Wind ◽  
A Current

The grain orientation of Sn-based solder joints on copper pillars under the combined action of electron wind force and temperature gradient greatly affects their electromigration damage. The copper pillars with Sn-1.8Ag lead-free solder on the top was subjected to a current density of 1.5 × 104 A/cm2 at 125 °C to study the electromigration behaviors. The grain orientation was characterized by scanning electron microscopy (SEM) equipped with electron backscattered diffraction (EBSD) detector. Metal dissolution and voids formation in the cathode as well as massive intermetallic compounds(IMC) accumulation in the anode were observed after electromigration. Closer examination of solder joints revealed that the Sn grain whose c-axis perpendicular to electric current may have retarded Cu diffusion to anode and IMC accumulation. In addition, the newly formed Cu6Sn5 exhibited preferred orientation related to the electric current direction.

Failure of Flip-Chip Circuit Interconnects under High Current Density

2010 ◽  
Vol 118-120 ◽  
pp. 449-453
Author(s):  
Yu Dong Lu ◽  
Xiao Qi He ◽  
Yun Fei En ◽  
Xin Wang ◽  
Zhi Qiang Zhuang
Keyword(s):  
Current Density ◽  
Flip Chip ◽  
Chemical Potential ◽  
High Current Density ◽  
Potential Gradient ◽  
High Current ◽  
Wind Force ◽  
Chemical Potential Gradient ◽  
Solder Bumps ◽  
Electron Wind

Both Al interconnects and flip-chip solder bumps were sensitive to high current. The failure mechanism of circuits interconnects would be more complicated if the current density in circuits was exceed the critical magnitudes of electromigration in both Al interconnects and solder bumps. The failure of circuit interconnects under different magnitudes of current density was studied and the interaction of electromigration in solder bumps and Al interconnects was discussed. The circuit interconnects of flip chip show three failure phenomena under high current density: voids in Al final metal, inter-diffusion of Al and SnPb, and melting of solder bumps. The voids in Al metal show the directional diffusion of Al atoms was mainly controlled by the electron wind fore. However the inter-diffusion of Al and SnPb demonstrated the electron wind force to Sn and Pb atoms would be ignored in contrast with chemical potential gradient or intrinsic stress. The flow of Sn and Pb atoms under high current density was in opposite direction with electron wind force and uniform with chemical potential gradient.

Prediction of Electromigration Induced Void and Hillock for IC Interconnect Structures

2013 ◽  
Vol 546 ◽  
pp. 6-11
Author(s):  
Yuan Xiang Zhang ◽  
Jun Wu ◽  
Ying Yu Ji
Keyword(s):  
Temperature Gradient ◽  
Density Gradient ◽  
Driving Force ◽  
Stress Gradient ◽  
Time To Failure ◽  
Wind Force ◽  
Numerical Example ◽  
Measurement Results ◽  
Hillock Formation ◽  
Electron Wind

This paper investigates the electromigration (EM) induced void and hillock generation in IC interconnect structures. The driving force for electromigration induced failure considered here includes the electron wind force, stress gradient, temperature gradient, as well as the atomic density gradient, which were neglected in many of the existing studies on eletromigration. The comparison of void/hillock formation and the time to failure (TTF) life through numerical example of the SWEAT structure with the measurement results are studied and discussed.

Electromigration and thermomigration behavior of flip chip solder joints in high current density packages

2008 ◽  
Vol 23 (9) ◽  
pp. 2333-2339 ◽  
Author(s):  
D. Yang ◽  
Y.C. Chan ◽  
B.Y. Wu ◽  
M. Pecht
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
High Current Density ◽  
Dominant Role ◽  
Current Crowding ◽  
Wind Force ◽  
Cross Sectional ◽  
Ambient Temperatures ◽  
Atomic Flux ◽  
Electron Wind

The electromigration and thermomigration behavior of eutectic tin-lead flip chip solder joints, subjected to currents ranging from 1.6 to 2.0 A, at ambient temperatures above 100 °C, was experimentally and numerically studied. The temperature at the chip side was monitored using both a temperature coefficient of resistance method and a thermal infrared technique. The electron wind force and thermal gradient played the dominant role in accelerated atomic migration. The atomic flux of lead due to electromigration and thermomigration was estimated for comparison. At the current crowding region, electromigration induced a more serious void accumulation as compared with thermomigration. Also, because of different thermal dissipations, a morphological variation was detected at different cross-sectional planes of the solder joint during thermomigration.

Influence of the Electric Current Pulse with Different Pulse Width on the Eutectoid Microstructure of Hypoeutectic Fe-C Alloys

2014 ◽  
Vol 852 ◽  
pp. 208-213
Author(s):  
Zheng Yang Huang ◽  
Qi Hong Cen ◽  
Zhen Hua Li ◽  
Ying Wu ◽  
Lei Zou
Keyword(s):  
Electric Current ◽  
Current Pulse ◽  
Joule Heating ◽  
Pulse Width ◽  
Dislocation Motion ◽  
Electric Current Pulse ◽  
Wind Force ◽  
Cementite Dissolution ◽  
Pile Up ◽  
Electron Wind

The influence of the eutectoid structure of hypoeutectic Fe-C alloys by applying electric current pulse (ECP) is carried out. The experiment results show that ECP treatment can produce Joule heating. Joule heating increases the diffusion capability of atoms and the driving force of austenite growth, which promotes austenite crystal growth and accelerate cementite dissolution. In view of the influence of the electron-wind-force made by ECP, it can increase the quantity of moving dislocation. The dislocation pile-up which made by the dislocation motion lead to cementite dissolution. Cementite dissolution can lead to concentration fluctuation in Austenite. ECP can also make the phase transformation barrier and the phase transition drive force of graphite formation decrease. As the result, these phenomena can make cryogenic ledeburite become less and graphite increase. Furthermore, it can also increase the nucleation rate and growth rate of ferrite, which can make the relative amount of ferrite increase and the relative amount of pearlite decrease. Based on our experiments, the effect becomes more obvious with the pulse width increase.

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