A Comparison of grain-boundary and matrix-crystalline fracture in Ti-Mo wires by scanning electron microscopy

1970 ◽  
Vol 5 (6) ◽  
pp. 534-537
Author(s):  
L. E. Murr
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Boundary ◽  
Crystalline Fracture ◽  
Scanning Electron

Intergranular Fatigue Cracking Enhanced by Impurity Segregation

2007 ◽  
Vol 539-543 ◽  
pp. 2137-2142 ◽  
Author(s):  
Claire Daniel ◽  
Frédéric Christien ◽  
René Le Gall
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Fatigue Cracking ◽  
Cold Drawing ◽  
High Concentration ◽  
Impurity Segregation ◽  
High Level ◽  
Scanning Electron

It was previously reported that fatigue life of some alloys can be dramatically reduced if the grain boundaries contain a high level of impurity segregation before fatigue tests. In this paper the susceptibility of single phase brass samples (90Cu10Zn) to this form of damage is studied. After cold drawing of as cast brass bars, fatigue samples were heat treated at 800°C during 30min to promote recrystallization and impurity segregation at grain boundary. The samples were then tested under high frequency bending fatigue test at 200°C. After cracking, fracture surfaces were studied using both scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The SEM micrographs showed that the fractures were mostly intergranular. Chemical composition of intergranular cracks surface were analyzed using EPMA at low accelerating voltage. A high concentration of sulfur was found on most of grain boundary facets. The internal stress in alloys after fatigue was qualitatively estimated using electron backscattering diffraction in scanning electron microscopy. A high level of local misorientation was found near most grain boundaries. The mechanism of intergranular cracks formation during fatigue is discussed taking into account both the segregation of sulfur at grain boundaries and accumulation of plastic strain at grain boundaries

Microstructural studies of Cu brazing on AlN

2001 ◽  
Vol 16 (3) ◽  
pp. 670-677 ◽  
Author(s):  
Chaoxian Cai ◽  
Janet K. Lumpp
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Boundary ◽  
Interfacial Reaction ◽  
Outer Boundary ◽  
Energy Dispersive ◽  
X Ray ◽  
Active Metal ◽  
Microstructural Studies ◽  
Scanning Electron

The microstructures and phase compositions of Cu–Ag–Ti active-metal brazing alloys have been studied by scanning electron microscopy and energy dispersive x-ray spectroscopy to evaluate alloy wetting on AlN and Cu brazing on AlN. Titanium is segregated from the original alloy, and a Ti-rich layer is formed between the brazing alloy and AlN substrate. The alloy components are able to penetrate into the grain boundary of AlN during wetting or brazing, and the interfacial reaction takes place along the grain and outer boundary of AlN. The bonding of brazing alloys to AlN substrate often induces cracks in the AlN side.

Microstructure and Properties of a Bismuth-Brass

2012 ◽  
Vol 486 ◽  
pp. 270-273 ◽  
Author(s):  
He Bing Han ◽  
Xin Min Huang ◽  
Yu Cheng Wu ◽  
Yong Qiang Qin ◽  
Jun Li Cao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Grain Boundary ◽  
X Ray Diffraction ◽  
Rich Phase ◽  
X Ray ◽  
Microstructure And Properties ◽  
Scanning Electron

The Cu-40wt%Zn-1.0wt%Bi-1.0wt%Mn bismuth-brass was prepared by casting and annealing. The microstructure was investigated by scanning electron microscopy (SEM), the phase composition was analyzed by X-ray diffraction (XRD), and the properties of mechanics and cutting were tested, too. The results show that the bismuth-rich phase is mainly distributed in the grain boundary as the shape of granules, which lead to the mechanics property and cutting property of bismuth-brass can basically reach the requirements of replace the traditional cutting-free brasses.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

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