Effect of Mesostructural Elements on Radiation-Induced Porosity in 16Cr-19Ni-2Mo-2Mn-Nb-Ti-V-P-B Austenitic Steel

2019 ◽  
Vol 946 ◽  
pp. 357-361
Author(s):  
Vladimir I. Pastukhov ◽  
Irina A. Portnykh ◽  
Mikhail L. Lobanov
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Boundaries ◽  
Austenitic Steel ◽  
Neutron Irradiation ◽  
Steel Structure ◽  
Void Size ◽  
Orientation Microscopy ◽  
Radiation Induced ◽  
Scanning Electron

Different mesostructural elements of 16Cr-19Ni-2Mo-2Mn-Nb-Ti-B austenitic steel have been examined after neutron irradiation to damage dose up to 82 dpa by scanning electron microscopy using orientation microscopy (EBSD). Radiation porosity with maximum void size up to 200 nm was observed in austenitic steel structure after neutron irradiation. Nonuniformity, related to mesostructural elements, such as general grain boundaries, special CSL boundaries Σ3 (twins), areas with high density of low-angle boundaries, is typical for radiation porosity.

Microstructure of Polycrystalline Sic Containing Excess Si after Neutron Irradiation

1980 ◽  
Vol 2 ◽  
Author(s):  
S.D. Harrison ◽  
J.C. Corelli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Neutron Irradiation ◽  
Black Spot ◽  
Excess Silicon ◽  
Transmission Electron ◽  
Scanning Electron ◽  
Sem Studies

ABSTRACTThe microstructure of commercially available reactionbonded polycrystalline SiC containing 8–10 wt% excess silicon was studied after irradiation by reactor neutrons uitlizing transmission electron microscopy (TEM) and scanning electron microscopy (SEM). For TEM studies on samples irradiated below 473°K we observe dislocation tangles near grain boundaries or impurities plus isolated dislocations throughout the remainder of the grain, whereas for irradiation temperatures of ≈3730°K the material exhibits copious quantities of “black spot” defects (2–5nm size) and a lower concentration of tangles than 473°K irradiation. The SEM studies of surfaces of samples fractured at 1473°K indicate that the mode of fracture is predominantly transgranular.

Effect of Pre-Rolling Reduction on Intergranular Corrosion of Aluminum Alloy 2519A

2007 ◽  
Vol 546-549 ◽  
pp. 1117-1122 ◽  
Author(s):  
Y. Liu ◽  
Xin Ming Zhang ◽  
B. Liu ◽  
Hui Zhong Li ◽  
Hui Gao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Aluminum Alloy ◽  
Grain Boundaries ◽  
Intergranular Corrosion ◽  
Discrete Distribution ◽  
Rolling Reduction ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Scanning Electron

The effect of pre-rolling reduction prior to ageing on the size and distribution of the precipitates, the width of precipitation free zones (PFZ) along grain boundaries and intergranular corrosion (IGC) of aluminum alloy 2519A were investigated by hardness tests, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results showed that the time for peak-age shortened when the reduction increased, which resulted in refining the precipitatates and distributing homogeneously within the grains and hence the IGC decreased. With increasing pre-rolling reduction, the PFZ along grain boundaries became narrower and precipitates changed from continuous chains to discrete distribution, which resulted in high IGC resistance.

scholarly journals Effect of sensitization on corrosion properties of TIG welded Al-Mg alloy

2020 ◽  
Vol 70 (1) ◽  
pp. 47-51
Author(s):  
Ljubica Radović ◽  
Jelena Marinković
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mass Loss ◽  
Grain Boundaries ◽  
Base Metal ◽  
Intergranular Corrosion ◽  
Corrosion Properties ◽  
Rich Phase ◽  
Hot Rolled ◽  
Scanning Electron

The effect of sensitization on the intergranular corrosion (IGC) of TIG welded AlMg6Mn was investigated by means of scanning electron microscopy (SEM) and corrosion NAMLT tests. The as-received hot rolled AlMg6Mn alloy plates with a thickness of 8 mm were welded by TIG welding with S-AlMg5 as a filler material. Specimens were sensitized at 100°C for 7 days. It was found that welded specimens are sensitive to IGC. The. mass loss in NAML test was 106.7 mg/cm². The welding increases the susceptibility to IGC, since the mass loss of the base metal at the same test was 70.7 mg/cm². The increase of susceptibility to IGC is attributed to significant continually precipitated Mg-rich phase along the grain boundaries during the sensitization treatment.

scholarly journals Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1515
Author(s):  
Halyna Klym ◽  
Ivan Karbovnyk ◽  
Andriy Luchechko ◽  
Yuriy Kostiv ◽  
Viktorija Pankratova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Composition ◽  
Grain Boundaries ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Spectroscopy Technique ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Scanning Electron

BaGa2O4 ceramics doped with Eu3+ ions (1, 3 and 4 mol.%) were obtained by solid-phase sintering. The phase composition and microstructural features of ceramics were investigated using X-ray diffraction and scanning electron microscopy in comparison with energy-dispersive methods. Here, it is shown that undoped and Eu3+-doped BaGa2O4 ceramics are characterized by a developed structure of grains, grain boundaries and pores. Additional phases are mainly localized near grain boundaries creating additional defects. The evolution of defect-related extended free volumes in BaGa2O4 ceramics due to the increase in the content of Eu3+ ions was studied using the positron annihilation lifetime spectroscopy technique. It is established that the increase in the number of Eu3+ ions in the basic BaGa2O4 matrix leads to the agglomeration of free-volume defects with their subsequent fragmentation. The presence of Eu3+ ions results in the expansion of nanosized pores and an increase in their number with their future fragmentation.

scholarly journals Enhancement the Osseo Integration Properties of Polymer for Human Body Implants

2020 ◽  
Vol 23 (4) ◽  
pp. 331-337
Author(s):  
Dhurgham Majid Rasheed ◽  
Dunya Abdulsahib Hamdi
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Grain Boundaries ◽  
Mechanical Performance ◽  
Wear Test ◽  
High Energy ◽  
In Vitro Test ◽  
Scanning Electron

In this research, polymer polymethyl methacrylate PMMA composite with nano ceramic Zr and HAp material were used to manufacture one part of the implant system (femoral ball head of hip implant). Three set of hybrid materials were fabricated and tested for this study; the first mixtures which contains 100% (PMMA), the second mixtures which contains (90% (PMMA) + 8% (Zr) + 2% (HAp)), and the third mixtures which contains (80% (PMMA) + 18% (Zr) + 2% (HAp)) were investigated. The mechanical properties for these mixtures increased with the increasing of nano ceramic concentration (Zr and HAp) composite material in the polymer compared to pure polymer PMMA sample. However, an increase in the concentration of Zr from 8% to 18% content cause a considerable decrease of the hardness where a drop of homogeneity in Zr- matrix PMMA contact occurred, V Hardness value are (68 ,80 and 70) Kg.mm for three mixture respectively. The wear test was in agreement with results of the hardness test. The weight loss of the above samples of the wear test were (0.041, 0.035 and 0.037) respectively. According to mechanical properties, the best sample contains (90% (PMMA) + 8% (Zr) + 2% (HAp)). The Scanning electron microscopy resolute showed the particles forming semi-continuous network along grain boundaries polymer for second sample mixtures containing (90% (PMMA) + 8% (Zr) + 2% (HAp)), provides a low atomic packing and high energy. This will make the grain boundaries more reactive and strengthen mechanical performance. The Optical microscopy, Scanning electron microscopy and Xray spectroscopy analysis for In vitro test using SBF shows the growth of HAp layer with an increase in concentration of Ca and P elements formed on the surface of the second sample. This display of good results is a proof of the biocompatibility of the polymer sample.

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

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