In Situ Observations of Voiding in Metal Lines Under Passivation

1994 ◽  
Vol 338 ◽  
Author(s):  
T. Marieb ◽  
J.C. Bravman ◽  
P. Flinn ◽  
M. Madden

ABSTRACTMovies showing high voltage scanning electron microscope (HVSEM) in situ observations of void motion in passivated metal lines were produced. By taking pictures of the line when the void morphology changes and combining these images digitally with a technique called morphing, a time-lapse movie is constructed with the minimum amount of stored images. The sequence of still images from which a movie is constructed are shown in this paper. This sequence demonstrates that wedge voids do not cause failure in near-bamboo pure Al lines; rather the void will move until it encounters a grain which it can grow across in a slit-like manner.

Author(s):  
Steven P. Jordan ◽  
Martin R. Bache ◽  
Christopher D. Newton ◽  
Louise Gale

Abstract The present paper will introduce the use of scanning electron microscope based, in-situ tensile testing as a method of detecting cracking in a SiCf/SiC CMC at room temperature. Small scale tensile specimens were prepared, but still sampling multiple longitudinal and transverse fibre tows. Monotonic loading was applied to initiate cracking, whilst contemporary time lapse imaging and retrospective digital image correlation recorded the development of these cracks at the specimen surface. Examples of strain localization, crack initiation and propagation will be presented for a plain gauge section specimen and single edge notched specimen. The critical combination of SEM imaging together with real time loading, in order to identify microscopic cracking in this CMC system, will be demonstrated.


Author(s):  
K. Tsuno ◽  
Y. Harada ◽  
T. Sato

Magnetic domains of ferromagnetic amorphous ribbon have been observed using Bitter powder method. However, the domains of amorphous ribbon are very complicated and the surface of ribbon is not flat, so that clear domain image has not been obtained. It has been desired to observe more clear image in order to analyze the domain structure of this zero magnetocrystalline anisotropy material. So, we tried to observe magnetic domains by means of a back-scattered electron mode of high voltage scanning electron microscope (HVSEM).HVSEM method has several advantages compared with the ordinary methods for observing domains: (1) high contrast (0.9, 1.5 and 5% at 50, 100 and 200 kV) (2) high penetration depth of electrons (0.2, 1.5 and 8 μm at 50, 100 and 200 kV). However, image resolution of previous HVSEM was quite low (maximum magnification was less than 100x), because the objective lens cannot be excited for avoiding the application of magnetic field on the specimen.


2014 ◽  
Vol 881-883 ◽  
pp. 1049-1052 ◽  
Author(s):  
Nai Peng ◽  
Cheng Ji Deng ◽  
Hong Xi Zhu

In this paper, the effects of briquetting pressure on the performance of in-situ formed Sialon in Al2O3-C refractory bricks are investigated. The phase compositions and microstructure of the Al2O3-C refractory were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM).The results show the briquetting pressure hardly has effect on the phase of the sintered specimens, two new phases of Sialon with a Z value of 2 and SiC formed. The micrographs of Sialon crystals have the shape of both column and tabular column, but with a cone tip in the specimens sintered at 200MPa and 300MPa and smooth tip in specimens sintered at 400MPa and 500MPa.


Holzforschung ◽  
1996 ◽  
Vol 50 (6) ◽  
pp. 487-490 ◽  
Author(s):  
Josef Bodner ◽  
Gerhard Grüll ◽  
Michael Georg Schlag

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1700 ◽  
Author(s):  
Xi-Shu Wang ◽  
Chang-Hao Tan ◽  
Juan Ma ◽  
Xiao-Dong Zhu ◽  
Qing-Yuan Wang

The low cycle fatigue tests on the crack initiation and propagation of cast magnesium alloys with two small holes were carried out by using in-situ scanning electron microscope (SEM) observation technology. The fatigue crack propagation behaviors and fatigue life, which are affected by two small artificial through holes, including the distances between two holes and their locations, were discussed in detail based on the experimental results and the finite element analysis (FEA). The results indicated that the fatigue multi-cracks occurred chiefly at the edges of two holes and the main crack propagation was along the weak dendrite boundary with the plastic deformation vestiges on the surface of α-Mg phase of cast AM50 and AM60B alloys. The fatigue cracking characteristics of cast AZ91 alloy depended mainly on the brittle properties of β-Mg17Al12 phase, in which the multi-cracks occurred still at the edges of two holes and boundaries of β-Mg17Al12 phase. The fatigue crack initiation position of cast magnesium alloys depends strongly on the radius of curvature of through hole or stress concentration factor at the closed edges of two through holes. In addition, the fatigue multi-cracks were amalgamated for the samples with titled 45° of two small holes of cast Mg-Al alloys when the hole distance is less than 4D (D is the diameter of the small hole).


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