Length Scale Effect on Deformation and Failure Mechanisms of Ultra-Fine Grained Aluminum

2005 ◽  
Vol 907 ◽  
Author(s):  
Khalid Hattar ◽  
J H Han ◽  
D M Follstaedt ◽  
S J Hearne ◽  
T A Saif ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Shear Failure ◽  
Failure Mechanisms ◽  
Deformation And Failure ◽  
Fine Grained ◽  
Transmission Electron ◽  
Microscopic Deformation ◽  
Different Thickness ◽  
Scanning Electron

AbstractThe deformation and failure processes in ultra-fine and nanograined metals over different length scales have been probed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in combination with a micromechanical in situ straining device. This novel straining device affords the opportunity to directly correlate the macroscopic mechanical properties with the microscopic deformation and failure mechanisms. Through use of this device it has been shown that increased film thickness results in a transition between limited plasticity and intergranular fracture to global plasticity and shear failure for deposited aluminum samples of similar grain size but different thickness.

Morphology of Polyethylene/Montmorillonite Nanocomposites Prepared by In Situ Polymerization

2013 ◽  
Vol 457-458 ◽  
pp. 244-247
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reflection Peak ◽  
Basal Reflection ◽  
Scanning Electron

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The morphology of MMT/MgCl2/TiCl4 catalyst and PE/MMT nanocomposites was investigated by scanning electron microscopy (SEM). It can be seen that MMT/MgCl2/TiCl4 catalyst remained the original MMT sheet structures and many holes were found in MMT and the morphology of PE/MMT nanocomposites is part of the sheet in the form of existence, as most of the petal structure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were carried out to characterize all the samples. XRD results reveal that the original basal reflection peak of PEI1 and PEI2 disappears completely and that of PEI3 become very weak. MMT/MgCl2/TiCl4 catalyst was finely dispersed in the PE matrix. Instead of being individually dispersed, most layers were found in thin stacks comprising several swollen layers.

scholarly journals Microstructures of Three In-Situ Reinforcements and the Effect on the Tensile Strengths of an Al-Si-Cu-Mg-Ni Alloy

2018 ◽  
Vol 8 (9) ◽  
pp. 1523 ◽  
Author(s):  
Lusha Tian ◽  
Yongchun Guo ◽  
Jianping Li ◽  
Feng Xia ◽  
Minxian Liang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Simultaneous Formation ◽  
X Ray ◽  
Transmission Electron ◽  
Ni Alloy ◽  
Al3ti Phase ◽  
Scanning Electron

In the present paper, the microstructures of three kinds of in-situ reinforcements Al-Ti-C, Al-Ti-B, and Al-Ti-B-C-Ce were deeply investigated using a combination of scanning electron microscopy, X-ray diffraction spectroscopy, and transmission electron microscopy. The effect of in-situ reinforcements on the room temperature and elevated temperature (350 °C) tensile strengths of Al-13Si-4Cu-1Mg-2Ni alloy were analyzed. It is found that doping with trace amounts of B and Ce, the size of the Al3Ti phase in the in-situ reinforced alloy changed from 80 µm (un-reinforced) to about 10 µm, with the simultaneous formation of the AlTiCe phase. The Al-Ti-B-C-Ce reinforcement which is rapid solidified, was more effective and superior to enhance the tensile strengths of the Al-13Si-4Cu-1Mg-2Ni alloy, both at room and high temperatures than those of addition other reinforcements. The room temperature (RT) strength increased by 19.0%, and the 350 °C-strength increased by 18.4%.

scholarly journals A Nanocellulose Polypyrrole Composite Based on Tunicate Cellulose

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Dawei Zhang ◽  
Qing Zhang ◽  
Xin Gao ◽  
Guangzhe Piao
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Ammonium Persulfate ◽  
High Electrical Conductivity ◽  
Chemical Polymerization ◽  
Transmission Electron ◽  
Mean Size ◽  
Polypyrrole Composite ◽  
Scanning Electron

The water-dispersed conductive polypyrrole (PPy) was prepared via thein situoxidative chemical polymerization by using ammonium persulfate (APS) as oxidant and tunicate cellulose nanocrystals (T-CNs) as a dopant and template for tuning the morphologies of PPy nanoparticles. Highly flexible paper-like materials of PPy/T-CNs nanocomposites with high electrical conductivity values and good mechanical properties were prepared. The structure of nanocomposites of PPy/T-CNs was investigated by using Fourier transform infrared spectroscopy. Scanning electron microscopy and transmission electron microscopy analyses of the composites revealed that PPy consisted of nanoparticles about 2.5 nm in mean size to form a continuous coating covered on the T-CNs. The diameters of the PPy nanoparticles increased from 10 to 100 nm with the increasing pyrrole amount. Moreover, electrical properties of the obtained PPy/T-CNs films were studied using standard four-probe technique and the electrical conductivity could be as high as 10−3 S/cm.

The Application of Scanning Electron Microscopy in the Investigation of Human Gastrointestinal Pathology

1973 ◽  
Vol 31 ◽  
pp. 430-431
Author(s):  
S. Siew
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Three Dimensional ◽  
Morphological Characteristics ◽  
Significant Advance ◽  
Gastrointestinal Pathology ◽  
Transmission Electron ◽  
Three Dimensional Configuration ◽  
Scanning Electron

A significant advance in our knowledge of gastrointestinal pathology has been achieved through endoscopy of the accessible portions of the alimentary tract. This procedure has allowed the evaluation of morphological characteristics of the mucosa by means of direct viewing in situ and through microscopy (light and transmission electron) of biopsies taken from selected areas. The importance of examination of the three dimensional configuration of the mucosal surface has been recognized, particularly in the assessment of the intestinal villi in cases of malabsorption, where it is recommended that the biopsies should be examined first by means of the dissecting microscope. Therefore, there is an obvious indication here for scanning electron microscopy, with its far greater potential.

In Situ Synthesis of Hybrid-Reinforced Titanium Matrix Composites

2007 ◽  
Vol 127 ◽  
pp. 155-160
Author(s):  
Di Zhang ◽  
Zhi Feng Yang ◽  
Wei Jie Lu ◽  
Dong Xu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Rare Earth ◽  
In Situ Synthesis ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
Transmission Electron ◽  
Scanning Electron

Novel hybrid TiB, TiC and rare earth oxide (Re2O3) reinforced titanium matrix composites were in situ synthesized utilizing the reaction between Ti, B4C (or C), rare earth (Re) and B2O3 through homogeneously melting in a non-consumable vacuum arc remelting furnace. In this work, Nd and Y were chosen as rare earth (Re) added in the in situ reaction. The thermodynamics of in situ synthesis reaction was studied. The results of X-ray diffraction (XRD) proved that no other phases appeared except for TiB, TiC and Re2O3. The microstructures of the composites were examined by scanning electron microscope (SEM) and backscattered scanning electron microscope (SEM). The results showed that there were mainly three kinds of reinforcements: TiB whiskers, TiC particles and Re2O3 particles. The reinforcements were fine and were homogeneously distributed in the matrix. The interfaces of TiB-TiC and Nd2O3-Ti were examined by high-resolution transmission electron microscopy (HREM).Transmission electron microscopy (TEM) and selected area diffraction (SAD) were used to analyze the orientation relationships of TiB-TiC and Nd2O3-Ti. The orientation relationship between TiB and TiC can be described as: [001] TiB //[001] TiC , (010) TiB //(110) TiC . The orientation relationship of Nd2O3 and α-Ti can be described as: [110] Nd2O3 //[ 1213 ] Ti , (111) Nd2O3 //(1101) Ti , ( 001) Nd2O3 //( 2110 ) Ti .

Observation of Electromigration Voiding in Cu Lines

1997 ◽  
Vol 473 ◽  
Author(s):  
Seok-Hee Lee ◽  
John C. Bravman ◽  
Paul A. Flinn ◽  
Lucile Arnaud
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Transmission Electron ◽  
Cu Film ◽  
Long Line ◽  
Film Characteristics ◽  
Voltage Scanning ◽  
Scanning Electron

ABSTRACTCu film characteristics and in-situ observation of electromigration voiding in passivated Cu lines are reported. Measured grain size distribution show a median grain size of 0.4 μm. A 3 μm wide, 800 μm long line passivated with 5000 Å of SiO2 was tested in a high voltage scanning electron microscopy (HVSEM), enabling dynamic in-situ events to be recorded. Electromigration voiding in this line showed some similarity to that previously observed in polygranular Al lines. Transmission electron microscopy was used to study the microstructure of the passivated Cu lines.

Microstructure and Hardness of NbC Coating Produced In Situ

2015 ◽  
Vol 1120-1121 ◽  
pp. 745-749 ◽  
Author(s):  
Xiao Long Cai ◽  
Li Sheng Zhong ◽  
Jie Fang Wang ◽  
Tian Tian Shao ◽  
Na Na Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Gray Cast Iron ◽  
Niobium Carbide ◽  
Oriented Attachment ◽  
Lattice Orientation ◽  
Transmission Electron ◽  
Scanning Electron

The niobium carbide (NbC) coating on gray cast iron has been produced by in situ which combined infiltration casting and heat treatment. The microstructural observations of the coating have been obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). And the growth mechanism of NbC grain was studied. The results show that the mechanism is orientation connection which means two particles of the same lattice orientation will be directly connected together and oriented attachment growth. Fine NbC grain can improve the nanohardness value of the coating with 23 GPa, meanwhile, it increase the elastic modulus with the value of 493.7 GPa.

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