Resistivity and Electron Microscopy Study of Precipitates in Fe-Ni-Co-Mo

1970 ◽  
Vol 28 ◽  
pp. 448-449
Author(s):  
A. Christou ◽  
R.W. Lowry
Keyword(s):  
Electron Microscopy ◽  
Precipitation Hardening ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Density Of Dislocations ◽  
Nucleation Sites ◽  
The Matrix ◽  
Hardening Mechanisms ◽  
Kinetics Of ◽  
Short Times

The details of the precipitation hardening mechanisms have been studied previously. Peters and Cupp have measured the kinetics of precipitation in an 18 pet Ni-Co-Mo steel. Hardy and Heal have studied the reversion processes caused by annealing for short times at temperatures above the aging temperature. This paper reports studies of the pre-precipitation and reversion stages in an 18 pct. Ni-Co-Mo steel (maraging with .46 pct Ti).The annealed microstructure of the parent steel consists of BCC martensitic grains. Within the matrix lies a fairly high density of dislocations whose configurations appear irregular. These dislocations are nucleation sites and are shown in Figure 1.

Newly formed phyllosilicates in rock matrices and fractures from CRP-3 core (Antarctica): an electron microscopy study

Clay Minerals ◽  
2007 ◽  
Vol 42 (1) ◽  
pp. 21-43 ◽  
Author(s):  
G. Giorgetti ◽  
F. S. Aghib ◽  
K. J. T. Livi ◽  
A.-C. Gaillot ◽  
T. J. Wilson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Marine Sediments ◽  
Ross Sea ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Secondary Phases ◽  
Transmission Electron Microscopy Study ◽  
Transmission Electron ◽  
The Matrix

AbstractA scanning and transmission electron microscopy study has been performed on Oligocene glacio-marine sediments, Devonian sandstones, and Jurassic dolerites recovered during CRP-3 drilling in the Ross Sea (Antarctica). Newly formed clay minerals occur in the rock matrices and as fillings in veins and faults which crosscut the whole sequence. Authigenic clays in sediments consist of beidellite-montmorillonite, berthierine/chlorite intergrowths and illite. Al,K-rich smectites and kaolinite occur in the Devonian sandstones. Saponite, berthierine/chlorite intergrowths, and Fe-hydroxides develop in the altered dolerites. Hence, the composition of the secondary phases depends also on the geochemistry of the rock they grow in. Within each sample, the same authigenic minerals form in the matrix and in the vein/fault. Clays precipitated from fluids, with variable fO2 values, which circulated in the system during the contemporaneous diagenetic and faulting events.

An In-situ Electron Microscopy Study of Microstructural Evolution in a Co-NbCo2 Binary Alloy

2008 ◽  
Vol 1128 ◽  
Author(s):  
Sharvan Kumar ◽  
Padam Jain ◽  
Seong Woong Kim ◽  
Frank Stein ◽  
Martin Palm
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Laves Phase ◽  
Face Centered Cubic ◽  
The Matrix ◽  
The Individual ◽  
Individual Grains

AbstractThe microstructure in a Co-rich, Co-15 at.% Nb alloy was characterized in the as-cast condition. A predominantly lamellar eutectic morphology composed of a Co-Nb solid solution and the C15 Laves phase NbCo2 was confirmed by transmission electron microscopy. The C15 phase was heavily twinned, with only one variant of twins being present in the individual lamella, while the Co solid solution had the face centered cubic structure. In-situ heating to 600°C in the microscope confirmed the decomposition of the metastable Laves phase into a fine equiaxed, ˜10-20 nm grain size microstructure, and the product phase is the monoclinic Nb2Co7. The individual grains appear faulted. The matrix solid solution retained the fcc structure and no change in structure was observed on cooling to room temperature. Heating to temperatures as high as 1130°C leads to rapid grain growth in the Nb2Co7 phase, and the nucleation and growth of a few new grains within the original grains; however, the reverse peritectoid transformation previously reported, was not observed.

An Electron Microscopy Study of the Kinetics of the Destruction of Polymer–Fiber Adhesion Joints

2021 ◽  
Vol 14 (3) ◽  
pp. 370-375
Author(s):  
A. Ya. Gorenberg ◽  
Yu. A. Gorbatkina ◽  
V. G. Ivanova-Mumzhieva
Keyword(s):  
Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Polymer Fiber ◽  
Kinetics Of

A photomicrographic and electron microscopy study of nucleation in ammonium perchlorate

1970 ◽  
Vol 318 (1533) ◽  
pp. 197-211 ◽  
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Ammonium Perchlorate ◽  
Critical Size ◽  
Crystal Surface ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Original Material ◽  
Microscope Examination ◽  
Nucleation Sites

The nucleation processes associated with the formation of thermal decomposition sites in single crystals of ammonium perchlorate have been studied by optical and electron microscopy. In crystals subjected only to heating the nucleation sites appear to be randomly distributed on the c face ; however, on the m face some are randomly distributed but others lie along lines in specific crystallographic directions. When crystals are strained, in any of several different directions, before thermal decomposition the nuclei are strongly alined on both faces. These alined nuclei lie, with few exceptions, in the same crystallographic directions as similarly alined p its formed by chemical etching. Consequently, it is concluded that the decomposition nuclei preferentially form where dislocations intersect the crystal surface. During heating at 170 to 210 °C the first-formed nuclei are widely distributed and appear to be on the surface. These and subsequently formed nuclei appear to cease growing when they reach a critical size. Additional nuclei continually appear between previously formed ones until a completely reacted layer is formed. (At these low temperatures complete reaction corresponds to the decomposition of only 30 % of the original material.) Further decomposition occurs in two ways. In one, the reaction progresses inward and roughly parallel to the surface as successively deeper layers of nuclei are formed. In the other, the reaction produces bands, possibly at an accelerated rate and with the formation of additional internal nuclei, along (001) planes in the [010] and [510] directions. Scanning electron microscope examination shows that these bands, as well as other parts of the reacted surface, consist of porous residue of ammonium perchlorate.

Electron microscopy of a Gd–Ba–Cu–O superconductor

1989 ◽  
Vol 4 (3) ◽  
pp. 515-520 ◽  
Author(s):  
R. Ramesh ◽  
G. Thomas ◽  
R. L. Meng ◽  
P. H. Hor ◽  
C. W. Chu
Keyword(s):  
Electron Microscopy ◽  
Microscopy Study ◽  
Annealed Sample ◽  
Electron Microscopy Study ◽  
Zone Axis ◽  
Matrix Phase ◽  
The Matrix ◽  
Tetragonal Form ◽  
Convergent Beam ◽  
Beam Patterns

An electron microscopy study has been carried out to characterize the microstructure of a sintered Gd–Ba–Cu–O superconductor alloy. The GdBa2Cu3O7−x phase in the oxygen annealed sample is orthorhombic while in the vacuum annealed sample it is tetragonal. It is shown that the details of the fine structure in the [001] zone axis convergent beam patterns can be used to distinguish between the orthorhombic form and the tetragonal form. In addition to this matrix phase, an amorphous phase is frequently observed at the triple grain junctions. Gd-rich inclusions have been observed inside the matrix phase.

Nucleation and growth kinetics of spiral steps on TiN(111): Anin situlow-energy electron microscopy study

2005 ◽  
Vol 98 (3) ◽  
pp. 034901 ◽  
Author(s):  
S. Kodambaka ◽  
J. Bareño ◽  
S. V. Khare ◽  
W. Święch ◽  
I. Petrov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Growth Kinetics ◽  
Microscopy Study ◽  
Nucleation And Growth ◽  
Electron Microscopy Study ◽  
Energy Electron ◽  
Kinetics Of
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