Interaction between Lattice Dislocations and Grain Boundaries in Ordered Compounds: Theory and Experiment

1990 ◽  
Vol 186 ◽  
Author(s):  
B. J. Pestman ◽  
J. Th. M. De Hosson ◽  
V. Vitek ◽  
F.D. Tichelaar ◽  
F.W. Schapink

AbstractThe interaction between a screw dislocation and symmetric [1 1 0] tilt boundaries under the influence of an applied shear stress was investigated by atomistic simulation. Many-body potentials representing Cu and Ni3Al were used for the description of the interatomic forces. A comparison will be made with in-situ observations in a transmission electron microscope of the interaction of screw dislocations with a coherent twin boundary.

1990 ◽  
Vol 213 ◽  
Author(s):  
B.J. Pestman ◽  
J. Th. M. De Hosson ◽  
V. Vitek ◽  
F.W. Schapink

ABSTRACTThe interaction of 1/2<1 1 0> screw dislocations with symmetric [1 1 0] tilt boundaries was investigated by atomistic simulations using many-body potentials representing ordered compounds. The calculations were performed with and without an applied shear stress. The observations were: absorption into the grain boundary, attraction of a lattice Shockley partial dislocation towards the grain boundary and transmission through the grain boundary under the influence of a shear stress. It was found that the interaction in ordered compounds shows similarities to the interaction in fcc.


Author(s):  
T. Marieb ◽  
J. C. Bravman ◽  
P. Flinn ◽  
D. Gardner ◽  
M. Madden

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2229 ◽  
Author(s):  
Flora Somidin ◽  
Hiroshi Maeno ◽  
Xuan Tran ◽  
Stuart D. McDonald ◽  
Mohd Mohd Salleh ◽  
...  

In-situ observations of the polymorphic transformation in a single targeted Cu6Sn5 grain constrained between Sn-0.7 wt % Cu solder and Cu-Cu3Sn phases and the associated structural evolution during a solid-state thermal cycle were achieved via a high-voltage transmission electron microscope (HV-TEM) technique. Here, we show that the monoclinic η′-Cu6Sn5 superlattice reflections appear in the hexagonal η-Cu6Sn5 diffraction pattern upon cooling to isothermal 140 °C from 210 °C. The in-situ real space imaging shows that the η′-Cu6Sn5 contrast pattern is initiated at the grain boundary. This method demonstrates a new approach for further understanding the polymorphic transformation behavior on a real solder joint.


2020 ◽  
Author(s):  
Tingting Yang ◽  
Hui Li ◽  
Yongfu Tang ◽  
Jingzhao Chen ◽  
Hongjun Ye ◽  
...  

Abstract The growth of lithium (Li) whiskers is detrimental to Li batteries. However, it remains a challenge to directly track Li whisker growth. Here we report in situ observations of electrochemically induced Li deposition under a CO2 atmosphere inside an environmental transmission electron microscope. We find that the morphology of individual Li deposits is strongly influenced by the competing processes of cracking and self-healing of the solid electrolyte interphase (SEI). When cracking overwhelms self-healing, the directional growth of Li whiskers predominates. In contrast, when self-healing dominates over cracking, the isotropic growth of round Li particles prevails. The Li deposition rate and SEI constituent can be tuned to control the Li morphologies. We reveal a new “weak-spot” mode of Li dendrite growth, which is attributed to the operation of the Bardeen-Herring growth mechanism in the whisker’s cross section. This work has implications for the control of Li dendrite growth in Li batteries.


Author(s):  
Nobuo Tanaka ◽  
Takeshi Fujita ◽  
Yoshimasa Takahashi ◽  
Jun Yamasaki ◽  
Kazuyoshi Murata ◽  
...  

A new environmental high-voltage transmission electron microscope (E-HVEM) was developed by Nagoya University in collaboration with JEOL Ltd. An open-type environmental cell was employed to enable in-situ observations of chemical reactions on catalyst particles as well as mechanical deformation in gaseous conditions. One of the reasons for success was the application of high-voltage transmission electron microscopy to environmental (in-situ) observations in the gas atmosphere because of high transmission of electrons through gas layers and thick samples. Knock-on damages to samples by high-energy electrons were carefully considered. In this paper, we describe the detailed design of the E-HVEM, recent developments and various applications. This article is part of a discussion meeting issue ‘Dynamic in situ microscopy relating structure and function'.


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