scholarly journals Thermal Annealing of Solid Kr Precipitates in Ni

1989 ◽  
Vol 157 ◽  
Author(s):  
R. C. Birtcher ◽  
J. Rest ◽  
D. S. Bergstrom
Keyword(s):  
Size Distribution ◽  
Thermal Annealing ◽  
Room Temperature ◽  
Precipitate Size ◽  
Rate Theory ◽  
Bimodal Size Distribution ◽  
Transmission Electron ◽  
Precipitate Size Distribution ◽  
Subsequent Thermal Annealing ◽  
Annealing Experiments

ABSTRACTAfter implantation into Ni at room temperature, Kr condenses under high pressure as an fee solid aligned with the Ni lattice. Evolution of these precipitates during subsequent thermal annealing to a temperature of 650 C has been followed with transmission electron microscopy and modeled with rate theory.Room temperature implantation results in a monomodal size distribution of small solid Kr precipitates. When Kr is implanted into Ni at 500 C, some precipitates grow to larger sizes, and the precipitate size distribution becomes bimodal. Annealing to temperatures below 600 C after room temperature implantation produces a bimodal size distribution consisting of small solid Kr precipitates and large Kr bubbles. Annealing above 600 C leads to more complete precipitate motion and coalescence that eliminates all small precipitates and results in a monomodal size distribution of large faceted bubbles.Rate-theory modelling of Kr implantation into Ni at 500 C suggests that small solid Kr precipitates are immobile and that Kr melting is required for precipitate mobility. Similar calculations for thermal annealing experiments show that the bubble size distribution becomes bimodal when only a small fraction of the small precipitates melt and become mobile during annealing, while the size distribution remains monomodal when all precipitates become mobile after Kr melting at higher temperatures.

Formation of (Fe,Cr) carbides and dislocation structures in low-chromium steel studiedin situusing synchrotron radiation

2012 ◽  
Vol 46 (1) ◽  
pp. 181-192 ◽  
Author(s):  
E. Gözde Dere ◽  
Hemant Sharma ◽  
Richard M. Huizenga ◽  
Giusseppe Portale ◽  
Wim Bras ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Room Temperature ◽  
Rapid Heating ◽  
Chromium Steel ◽  
Dispersion Parameter ◽  
Precipitate Size ◽  
Two Dimensional ◽  
X Ray ◽  
Transmission Electron

The evolution of the size distribution of (Fe,Cr) carbides and the dislocation structure in low-chromium steel is studied during quenching and rapid heating byin situsmall-angle X-ray scattering (SAXS). The two-dimensional SAXS patterns consist of streaks on top of an isotropic SAXS signal. The evolution of the size distribution of the (Fe,Cr) carbides during heat treatment is determined from the isotropic component of the SAXS patterns. The isotropic part of the SAXS patterns shows that, after austenitization and quenching to room temperature, the average precipitate radius is 4.74 nm and the dispersion parameter for the lognormal size distribution is 0.33. Subsequent rapid heating to 823 K results in an average precipitate size of 5.25 nm and a dispersion parameter of 0.26. Bright-field transmission electron microscopy and high-resolution transmission electron microscopy reveal the nearly spherical morphology of the precipitates. The microstructural evolution underlying the increase in the average precipitate size and the decrease in the dispersion parameter after heating to and annealing at 823 K is probably that at room temperature two types of precipitates are present,i.e.(Fe,Cr)23C6and (Fe,Cr)7C3precipitates according to thermodynamic calculations, and at 823 K only (Fe,Cr)7C3precipitates are present. Additional measurements have been carried out on a single crystal of ferrite containing (Fe,Cr) carbides by combining three-dimensional X-ray diffraction (3DXRD) and SAXS during rotation of the specimen at room temperature, in order to investigate the origin of the streaks at low angles in the SAXS pattern. From simulations based on the theory of SAXS from dislocations, it is shown that the measured streaks, including the spottiness, in the two-dimensional SAXS patterns correspond to a dislocation structure of symmetric low-angle tilt boundaries, which in turn corresponds to the crystallographic orientation gradient in the single crystal of ferrite as measured by 3DXRD microscopy.

scholarly journals Creation of pure non-crystalline diamond nanostructures via room temperature ion irradiation and subsequent thermal annealing

2021 ◽  
Author(s):  
Federico Picollo ◽  
Alfio Battiato ◽  
Federico Bosia ◽  
Fabio Scaffidi Muta ◽  
Paolo Olivero ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Group Iv ◽  
Chemical Bonds ◽  
Group Iv Elements ◽  
Silicon And Germanium ◽  
Subsequent Thermal Annealing

Carbon exhibits a remarkable range of structural forms, due to the availability of sp3, sp2 and sp1 chemical bonds. Contrarily to other group IV elements such as silicon and germanium,...

Effect of Self-Interstitials – Nanovoids Interaction on Two-Dimensional Diffusion and Activation of Implanted B in Si

2005 ◽  
Vol 108-109 ◽  
pp. 395-400 ◽  
Author(s):  
Filippo Giannazzo ◽  
E. Bruno ◽  
S. Mirabella ◽  
G. Impellizzeri ◽  
E. Napolitani ◽  
...  
Keyword(s):  
Thermal Annealing ◽  
Device Fabrication ◽  
Electrical Activation ◽  
High Dose ◽  
Dimensional Diffusion ◽  
Transmission Electron ◽  
Sio2 Mask ◽  
The Impact ◽  
Subsequent Thermal Annealing

In this work, we investigate the effect of performing a high dose 20 keV He+ implant before the implantation of B at low energy (3 keV) in silicon and the subsequent thermal annealing at 800 °C. The implants were performed in laterally confined regions defined by opening windows in a SiO2 mask, in order to evidence the impact on a realistic configuration used in device fabrication. High resolution quantitative scanning capacitance microscopy (SCM) combined with cross-section transmission electron microscopy (XTEM) allowed to clarify the role of the voids distribution produced during the thermal annealing on the diffusion and electrical activation of implanted B in Si. Particular evidence was given to the effect of the uniform nanovoids distribution, which forms in the region between the surface and the buried cavity layer.

Room-temperature synthesis of submicron platinum and palladium powders in glycols

1999 ◽  
Vol 14 (9) ◽  
pp. 3707-3712 ◽  
Author(s):  
K. Tekaia-Elhsissen ◽  
F. Bonet ◽  
S. Grugeon ◽  
S. Lambert ◽  
R. Herrera-Urbina
Keyword(s):  
Size Distribution ◽  
Room Temperature ◽  
Spherical Particles ◽  
Average Particle ◽  
Particle Sizes ◽  
Temperature Synthesis ◽  
Bimodal Size Distribution ◽  
Hydrazine Reduction ◽  
Average Size ◽  
Palladium Particles

Platinum and palladium powders with average particle sizes in the submicron range have been synthesized at room temperature by hydrazine reduction of and , respectively, in glycols. Platinum powders contain spherical particles with a bimodal size distribution. Palladium powders also contain spherical particles, but the size distribution is narrow. The effect of both ammonia and hydrazine concentration on the size distribution and average size of palladium particles was investigated.

scholarly journals In Situ Investigation with Neutrons on the Evolution of γ ' Precipitates at High Temperatures in a Single Crystal Ni-Base Superalloy

2011 ◽  
Vol 278 ◽  
pp. 42-47 ◽  
Author(s):  
Ralph Gilles ◽  
Debashis Mukherji ◽  
H. Eckerlebe ◽  
Pavel Strunz ◽  
Joachim Rösler
Keyword(s):  
Single Crystal ◽  
Size Distribution ◽  
Elevated Temperatures ◽  
Precipitate Size ◽  
Temperature Changes ◽  
Precipitate Size Distribution ◽  
Long Time ◽  
Sem Imaging ◽  
Base Superalloy

Single crystal Ni-base superalloys based on the  /  system are widely used in gas turbine applications. To understand the formation of  precipitates, including size distribution and growth, we performed in situ small-angle neutron scattering (SANS) measurements at elevated temperatures and - together with TEM as well as , SEM imaging - studied changes in the precipitates in short and long time scale. In the early stages, a bimodal precipitate size distribution of precipitate is observed, which (depending on the annealing temperature) changes to a cuboidal or nearly spherical morphology with almostmore or less uniform ( unimodal?) size distribution. [Note: The term "more or less" is several times repeated in the text. I cannot imagine what it in fact means. Could you change it or explain in a more clear way?]

Microstructural Comparison of an Al-8.0Zn-1.8Mg-2.0Cu Alloy with Typical T6 and T76 Tempers

2018 ◽  
Vol 941 ◽  
pp. 753-758
Author(s):  
Bai Qing Xiong ◽  
Kai Wen ◽  
Yong An Zhang ◽  
Zhi Hui Li ◽  
Xi Wu Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Precipitate Size ◽  
Imaging Analysis ◽  
Bright Field ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Precipitate Size Distribution ◽  
The Matrix

In order to analyze aging behavior of an Al-8.0Zn-1.8Mg-2.0Cu alloy, the microstructure of the alloy subjected to T6 and T76 states are investigated by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). Based on the precipitate observations, precipitate size distributions and average precipitate size are extracted from bright-field TEM images projected along 〈110〉Alorientation with the aid of an imaging analysis. The results indicate that the main precipitates are GPI zone, GPII zone and η' phase in the T6 alloy while η' phase and η phase in the T76 alloy. The bright-field TEM observations reveal that the matrix precipitates for the T6 alloy have small size and dispersive distribution while that for the T76 alloy has big size and sparse distribution. Both have discontinuously distributed grain boundary precipitates. Quantitative structural information including precipitate size distribution and average precipitate size has been calculated by an image analysis based on the bright-field TEM images projected along 〈110〉Alorientation. The results show that the T6 alloy has a narrower precipitate size range than the T76 alloy and thus the T6 alloy possesses a smaller average precipitate size than the T76 alloy.

Evolution of Cubic FeSi2 in Si upon Thermal Annealing

1993 ◽  
Vol 311 ◽  
Author(s):  
X.X. Lin ◽  
J. Desimoni ◽  
H. Bemas ◽  
Z. Liliental-Weber ◽  
J. Washburn
Keyword(s):  
Electron Microscopy ◽  
Thermal Annealing ◽  
Room Temperature ◽  
Ion Beam ◽  
Cubic Phase ◽  
Precipitate Coarsening ◽  
Transmission Electron ◽  
Higher Temperature ◽  
Induced Crystallization ◽  
Fe Implantation

ABSTRACTCubic FeSi2 precipitates were produced in Si (001) wafers by Fe implantation at room temperature, followed by ion beam-induced crystallization at 320°C, and their stability upon thermal annealing was examined by transmission electron microscopy. We found that the cubic phase remains relatively stable for a 650°C anneal, but the precipitates tend to change from an aligned to a twinned orientation with respect to the Si matrix. For higher temperature (800 and 900°C) anneals, most of the precipitates are transformed into β-FeSi2, accompanied by substantial precipitate coarsening. For platelet-shaped precipitates, the coarsening activation energy was determined to be 3.48 eV.

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