Morphology of fracture surfaces

Large propagation velocity and morphology of fractured surfaces... 

Fig. 2.29 Morphologies of fracture surfaces of green zirconia ceramic moulds with different PSDs a CSZl b CSZ2 c CSZ3 [15], With kind permission of Elsevier...

The surface morphologies of fractured surfaces of nanobiocomposites were observed with scanning electron microscope (SEM, S-4800, Hitachi, Japan) and energy dispersive X-ray (EDX). The fractured surface of biocomposites was prepared with impact test specimens. Prior to the observation, all the specimens were coated with Au in order to prevent electrical discharge. The acceleration voltage used was 15-25 kV. 

Scanning electron microscopy has been utilized to investigate the morphology of fracture surfaces and smoothed surfaces after etching of samples of PBT and blends. Samples as obtained from polymerization have been first compression-moulded at 260°C and then fractured in liquid N2. Smoothed surfaces have been obtained by using a microtome and analyzed after exposure to xylene or o-dichlorobenzene (blend PBTESI0.5) vapor. 

Figure 3. SEM morphologies of fracture surface of the C/C-ZrB -ZrC-SiC composite (sample B) (a. low and b. high magnifications)...

Microscopy. Three levels of magnification were required to characterize adequately the morphology of the molded polymer samples and of fracture surfaces after the impact test. A low power binocular microscope covering the magnification range from 2 to 12 times permitted initial evaluation of the fracture surface after which specific areas and... 

Siebert and Riew (4) described the chemistry of the in situ particle formation. They proposed that the composition of the particle is a mixture of linear CTBN-epoxy copolymers and crosslinked epoxy resin. The polymer morphology of the CTBN toughened epoxy systems was investigated by Rowe (5) using transmission electron microscopy by carbon replication of fracture surfaces. Riew and Smith (6) supported the... 

Fracture Surface Morphology. Although full details will be published separately, preliminary observations of fracture surface morphology were made on an ETEC scanning electron microscope, using specimens that had been coated with gold and carbon prior to examination. 

Fracture Surface Morphology. While a complete study of fracture surface morphology and the micromechanisms of failure is still in progress, preliminary examination revealed major differences between the modified and neat PVC s. These are now being interpreted in order to elucidate the micromechanism of failure. 

Electron microscopy can provide valuable information about morphological changes in the fibres, and can potentially give an indication of the nature and cause of degradation, such as photolytic damage, swelling, desiccation or abrasion. The appearance of fracture surfaces is a particularly useful source of information. 

The relationship between the impact properties and morphology in ICP has been studied extensively. For example. Tan et al. (4) and Cai et al. (5) examined the effect of morphology on the impact strength using ICP samples with similar ethylene content, molecular weight, and molecular weight distribution. A typical SEM micrograph of fractured surface ICP specimens after the impact test at — 20°C is shown in Fig. 8.3. 

The polymers, whose characteristics are summarized in Table 1, were melt mixed in a Brabender-like apparatus at 200 C and at two residence times 6 min, at 2 r.p.m. and further 10 min. at 32 r.p.m. The blend compositions are listed in Table 2. After premixing, cylindrical specimens were obtained directly by extrusion using a melting-elastic miniextruder (CSI max mixing extruder mod. CS-194), Thermal and tensile mechanical tests were performed on these specimens by an Instron Machine (mod. 1122) at room temperature and at cross-head speed of 10 mm/min. Also made were morphological studies by optical microscopy of sections microtomed from tensile samples and scanning electron microscopy of fractured surfaces of samples broken at liquid nitrogen temperature. Further details on the experimental procedures and on the techniques used are reported elsewhere . 

Fig. 4 shows the morphologies of fractured cement pastes with and without SBR dispersion or powder observed by ESEM. Irregular hydrates is observed on the surface of cement particles in the control paste after 10 minutes, and AFt or calcium aluminate hydrates with relative regular shape are also found (Fig. 4 (a)) while at this time a polymer-particle layer is seen on the surface of cement particles in the pastes with SBR dispersion or powder, and AFt or calcium aluminate hydrates appear among the polymer particles (Fig. 4 (b) (c)). 

Figure 4.38c shows fracture morphology of the green body, which had a very dense microstracture. No gap was observed across the fracture surface, implying the close compaction of the slices. Fracture morphology of pohshed surface of the YAG ceramics is shown in Fig. 4.38d. The sintered ceramics were nearly fully dense, without the presence of cracks on the surface, i.e., no delamination occurred during the binder removal and the sintering process. The average grain size of the YAG ceramics sintered at 1750 °C for 10 h was about 15 pm, while the in-line transmittance of the sample is 81.5 % at 1064 nm. Therefore, this is a flexible and feasible method to fabricate transparent ceramics with composite structures [163].

Figure 1.11 Aluminum nitride particle morphology (a) fracture surface of AIN cake, (b) general view at = 1890°C, and (c) conglomerate disintegration by "chemical dispergation."...

The fractured morphology of the surface in Figure 2.15b clearly indicates that the material has undergone major phase and structural (metal (cubic) oxide (triclinic)) changes prior to re-conversion to the metal again. This is corroborated by the EDS spectra collected after each event and is shown in Figure 2.16. 

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