scholarly journals Characterizing Precipitation Defects in Nickel Based 718 Alloy

2010 ◽  
Vol 636-637 ◽  
pp. 517-522 ◽  
Author(s):  
Aliou Niang ◽  
Julitte Huez ◽  
Jacques Lacaze ◽  
Bernard Viguier
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Stacking Fault ◽  
Crystallographic Structure ◽  
Chemical Ordering ◽  
Transmission Electron ◽  
Matrix Dislocation ◽  
Nickel Base

In the present study we examine the crystallographic structure of the , ’’ and  phases present in nickel base 718 alloy. The chemical ordering of Nb atoms and possible planar faults that may be observed in ’’ precipitates are detailed. High resolution transmission electron microscopy (HRTEM) observations of various faults are reported. The decomposition of a matrix dislocation to form a locked V shaped configuration is shown. The observation along [110] type direction allows to identify the type of defect, which is observed as a pure geometric stacking fault.

scholarly journals Microstructure Evolution in He-Implanted Si at 600 °C Followed by 1000 °C Annealing

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5107
Author(s):  
Zhen Yang ◽  
Zhiping Zou ◽  
Zeyang Zhang ◽  
Yubo Xing ◽  
Tao Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Single Crystal ◽  
Microstructure Evolution ◽  
Cavity Growth ◽  
Stacking Fault ◽  
Structural Defects ◽  
Dislocation Loops ◽  
Transmission Electron

Si single crystal was implanted with 230 keV He+ ions to a fluence of 5 × 1016/cm2 at 600 °C. The structural defects in Si implanted with He at 600 °C and then annealed at 1000 °C were investigated by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The microstructure of an as-implanted sample is provided for comparison. After annealing, rod-like defects were diminished, while tangled dislocations and large dislocation loops appeared. Dislocation lines trapped by cavities were directly observed. The cavities remained stable except for a transition of shape, from octahedron to tetrakaidecahedron. Stacking-fault tetrahedrons were found simultaneously. Cavity growth was independent of dislocations. The evolution of observed lattice defects is discussed.

Nanomechanical Analysis of Triangular Defect in 4H-SiC Epilayer

2014 ◽  
Vol 778-780 ◽  
pp. 394-397 ◽  
Author(s):  
Yun Ji Shin ◽  
Soo In Kim ◽  
Hyeon Jin Jung ◽  
Chang Woo Lee ◽  
Wook Bahng
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
High Resolution ◽  
Stacking Faults ◽  
Crystallographic Structure ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
Micro Raman Spectroscopy ◽  
Transmission Electron

We report an investigation of the formation of triangular defects (TDs) in 4H–SiC expitaxial layers using Kelvin probe force microscopy (KPFM) and a nano-indenter. The results provide valuable information on the crystallographic structure, including the polytype nature of the TDs and surface potential profile. The TDs were also characterized using micro-Raman spectroscopy and high-resolution transmission electron microscopy. We found that the TDs were composed of a thick 3C-SiC band, as well as stacking faults (SFs) in the 4H-SiC epilayer.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Improved quantification of curvature in high-resolution transmission electron microscopy lattice fringe micrographs of soots

Carbon ◽  
2017 ◽  
Vol 117 ◽  
pp. 174-181 ◽  
Author(s):  
Chang’an Wang ◽  
Thomas Huddle ◽  
Chung-Hsuan Huang ◽  
Wenbo Zhu ◽  
Randy L. Vander Wal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Lattice Fringe ◽  
Transmission Electron
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