High-resolution transmission electron microscopy investigation of the face-centered cubic/hexagonal close-packed martensite transformation in Co-31.8 wt pct Ni alloy: Part 1. Plate interfaces and growth ledges

1996 ◽  
Vol 27 (11) ◽  
pp. 3362-3370 ◽  
Author(s):  
D. W. Bray ◽  
J. M. Howe
2000 ◽  
Vol 636 ◽  
Author(s):  
S. Yamamuro ◽  
D. Farrell ◽  
K. D. Humfeld ◽  
S. A. Majetich

AbstractArrays were self-assembled by evaporating suspensions of 4 nm FePt or 8 nm Fe nanoparticles. The monolayers had a hexagonal close packed (hcp) structure, but the multilayer structure varied. To identify the multilayer structures, transmission electron microscopy (TEM) images were compared with phase contrast image simulations. The results showed that Fe could be grown as both hcp and face-centered cubic (fcc), or fcc-like, structures. The results of image analysis of the FePt arrays were consistent with fcc structures.


1991 ◽  
Vol 6 (4) ◽  
pp. 755-759 ◽  
Author(s):  
R. Allem ◽  
G. L'Espérance ◽  
Z. Altounian ◽  
J.O. Ström-Olsen

The microstructure of two metastable crystalline phases, which are formed during the first step of the crystallization process in Ni–Zr metallic glasses, was investigated by transmission electron microscopy. For the composition Ni33Zr67, crystallites with average size of 150 nm having the face-centered cubic E93 structure are formed. For the Ni42Zr58 composition, 100 nm size crystallites with a simple cubic unit cell, space group Pa3 are formed. The microstructure of the crystallites in the early stage of crystallization of the two phases is similar to globular morphology and internal striations.


2019 ◽  
Vol 25 (2) ◽  
pp. 320-330 ◽  
Author(s):  
Markus Kühbach ◽  
Andrew Breen ◽  
Michael Herbig ◽  
Baptiste Gault

AbstractThe process of building an open source library of simulated field desorption maps for differently oriented synthetic tips of the face-centered cubic, body-centered cubic, and hexagonal-close-packed crystal structures using the open source software TAPSim is reported. Specifically, the field evaporation of a total set of 4 × 101 single-crystalline tips was simulated. Their lattices were oriented randomly to sample economically the fundamental zone of crystal orientations. Such data are intended to facilitate the interpretation of low-density zone lines and poles that are observed on detector hit maps during Atom Probe Tomography (APT) experiments. The datasets and corresponding tools have been made publicly available to the APT community in an effort to provide better access to simulated atom probe datasets. In addition, a computational performance analysis was conducted, from which recommendations are made as to which key tasks should be optimized in the future to improve the parallel efficiency of TAPSim.


1997 ◽  
Vol 12 (5) ◽  
pp. 1268-1273 ◽  
Author(s):  
Jonathon J. Host ◽  
Mao H. Teng ◽  
Brian R. Elliott ◽  
Jin-Ha Hwang ◽  
Thomas O. Mason ◽  
...  

Graphite encapsulated nanocrystals produced by a low carbon tungsten arc were analyzed to determine their chemistry, crystallography, and nanostructural morphology. Metallic nanocrystals of Fe, Co, and Ni are in the face-centered cubic (fcc) phase, and no trace of the bulk equilibrium phases of body-centered cubic (Fe) and hexagonal close-packed (Co) were found. Various analytical techniques have revealed that the encased nanocrystals are pure metal (some carbide was found in the case of Fe), ferromagnetic, and generally spherical. The nanocrystals are protected by turbostratic graphite, regardless of the size of the nanocrystals. The turbostratic graphite coating is usually made up of between 2 and 10 layers. No trace of any unwanted elements (e.g., oxygen) was found. The low carbon: metal ratio arc technique is a relatively clean process for the production of graphite encapsulated nanocrystals.


1985 ◽  
Vol 62 ◽  
Author(s):  
J. Tafto ◽  
G. Rajeswaran ◽  
T. Saulys

ABSTRACTTICx films prepared by reactive sputtering using a Ti target and different methane partial pressures were characterized by analytical transmission electron microscopy. The films are polycrystalline, and the plasmon energy increases considerably with increasing carbon content. Combination of the information obtained from electron energy loss plasmon and core loss spectra, and electron diffraction indicates that x in TiCx increases linearly with methane partial pressure. We find that the face centered cubic TIC phase spans the composition from TiC0.2 to TiC1.0 and when x<l we have a mixture of TiC1.0 and amorphous C.


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