In situ annealing of aluminum ion-implanted with molybdenum

1983 ◽  
Vol 41 ◽  
pp. 260-261
Author(s):  
J. Bentley ◽  
L. D. Stephenson ◽  
R. B. Benson ◽  
P. A. Parrish
Keyword(s):  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Naval Research ◽  
Dislocation Network ◽  
Dislocation Loops ◽  
High Concentration ◽  
Aluminum Ion ◽  
Ion Implanted

As part of an analytical electron microscopy study of aluminum ion-implanted with molybdenum, in situ annealing experiments have been performed to better understand the phase transformation mechanisms in material with a peak molybdenum content of approximately 11 at. % Mo. Ion implantations were performed at the Naval Research Laboratory on electropolished coupons 38 × 28 × 0.5 mm of 99.999% Al with 0.5 mm grain size. A dual energy implant schedule of 1.12 × 1020 ions/m2 at 50 keV. plus 1.24 × 1020 ions/m2 at 110 keV was employed. The TEM specimens were prepared by electrodischarge machining 3-mm diameter disks from the implanted coupons and backthinning by electropolishing. In situ annealing was performed in a Philips EM 400T/FEG with the use of a Philips single-tilt heating holder. Videotape recordings were made from the TEM fluorescent viewing screen in the tilted position.A high concentration of small dislocation loops and possibly a tangled dislocation network were present in the as-implanted material. No precipitates were observed; this is consistent with a supersaturated solid solution.

scholarly journals In-Situ Analytical Electron Microscopy Study of the Lithiation of TiO2 Nanowires Used in Li-Ion Batteries

2013 ◽  
Vol 19 (S2) ◽  
pp. 1102-1103
Author(s):  
M. Gu ◽  
B. Li ◽  
W. Wang ◽  
V. Sprenkle ◽  
C.-M. Wang
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Li Ion Batteries ◽  
Tio2 Nanowires ◽  
Analytical Electron ◽  
Li Ion

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Analytical electron microscopy of aluminum ion-implanted with molybdenum

1983 ◽  
Vol 41 ◽  
pp. 262-263
Author(s):  
L. D. Stephenson ◽  
J. Bentley ◽  
R. B. Benson ◽  
P. A. Parrish
Keyword(s):  
Metastable Phase ◽  
Equilibrium Phase ◽  
Analytical Electron Microscopy ◽  
Microstructural Characterization ◽  
Equilibrium Phase Diagram ◽  
Naval Research ◽  
Aluminum Ion ◽  
Projected Range ◽  
Metastable Phase Formation ◽  
Ion Implanted

The microstructures of aluminum ion-implanted with molybdenum and subjected to various heat treatments are being investigated for correlation with nearsurface properties such as corrosion. Previous work indicated enhanced corrosion resistance, but dealt chiefly with the as-implanted condition and involved little microstructural characterization. In addition, the Al-Mo binary system is of interest because metastable phase formation was considered to be possible and the equilibrium phase diagram is poorly defined. Electropolished coupons 38 × 28 × 0.5 mm of 99.999% A1 with ∽0.5 mm grain size were implanted with Mo+ ions at the Naval Research Laboratory. The dual energy implant schedule of 4.88 × 1019 ions/m2 at 50 keV plus 6.14 × 1019 ions/m2 at 110 keV resulted in a peak concentration of 4.4 at. % Mo (measured by ion backscattering) within the projected range of ∽50 nm.Disks (3 imi diam) were electrodischarge machined from as-implanted specimens and then were backthinned by electropolishing.

scholarly journals Transmission Electron Microscopy Study In-Situ of Radiation-Induced Defects in Copper at Elevated Temperatures

1996 ◽  
Vol 439 ◽  
Author(s):  
T. L. Daulton ◽  
M. A. Kirk ◽  
L. E. Rehn
Keyword(s):  
Point Defects ◽  
Elevated Temperatures ◽  
Defect Density ◽  
Microscopy Study ◽  
High Energy ◽  
Dislocation Loops ◽  
Contrast Imaging ◽  
High Concentration ◽  
Transmission Electron

AbstractNeutrons and high-energy ions incident upon a solid can initiate a displacement collision cascade of lattice atoms resulting in localized regions within the solid containing a high concentration of interstitial and vacancy point defects. These point defects can collapse into various types of dislocation loops and stacking fault tetrahedra (SFT) large enough that their lattice strain fields are visible under diffraction-contrast imaging using a Transmission Electron Microscope (TEM). The basic mechanisms driving the collapse of point defects produced in collision cascades is investigated in situ with TEM for fcc-Cu irradiated with heavy (100 keV Kr) ions at elevated temperature. The isothermal stability of these clusters is also examined in situ.Areal defect yields were observed to decrease abruptly for temperatures greater than 300°C. This decrease in defect yield is attributed to a proportional decrease in the probability of collapse of point defects into clusters. The evolution of the defect density under isothermal conditions appears to be influenced by three different rate processes active in the decline of the total defect density. These rate constants can be attributed to differences in the stability of various types of defect clusters and to different loss mechanisms. Based upon observed stabilities, estimations for the average binding enthalpies of vacancies to SFT are calculated for copper.

Analytical Electron Microscopy Study of Second-Phase Particles in 7075 and 7475 Aluminum Alloys

1985 ◽  
Vol 43 ◽  
pp. 348-349
Author(s):  
M. Raghavan ◽  
J. Y. Koo ◽  
J. W. Steeds ◽  
B. K. Park
Keyword(s):  
Aluminum Alloys ◽  
Silicon Oxide ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Partial Substitution ◽  
Second Phase ◽  
X Ray ◽  
Second Phase Particles ◽  
Almost All

X-ray microanalysis and Convergent Beam Electron Diffraction (CBD) studies were conducted to characterize the second phase particles in two commercial aluminum alloys -- 7075 and 7475. The second phase particles studied were large (approximately 2-5μm) constituent phases and relatively fine ( ∼ 0.05-1μn) dispersoid particles, Figures 1A and B. Based on the crystal structure and chemical composition analyses, the constituent phases found in these alloys were identified to be Al7Cu2Fe, (Al,Cu)6(Fe,Cu), α-Al12Fe3Si, Mg2Si, amorphous silicon oxide and the modified 6Fe compounds, in decreasing order of abundance. The results of quantitative X-ray microanalysis of all the constituent phases are listed in Table I. The data show that, in almost all the phases, partial substitution of alloying elements occurred resulting in small deviations from the published stoichiometric compositions of the binary and ternary compounds.

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