Effect of Mg Contents on Trapping Efficiency in Al-Mg System Using PAS

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.265.7 ◽

2007 ◽

Vol 265 ◽

pp. 7-11

Author(s):

N.A. Kamel

Keyword(s):

Cross Sections ◽

Mg Alloys ◽

Trapping Efficiency ◽

Thickness Reduction ◽

Doppler Broadening ◽

Degree Of Deformation ◽

S Parameter ◽

Mean Lifetime ◽

The Mean ◽

Al Mg Alloys

PLT and the Doppler broadening S-parameter were used to characterize the Al-Mg alloys, AA5005, AA5051, AA5052 and AA5083. The trapping efficiencies of these alloys were estimated to be 2.42 x 109, 2.29 x 109, 2.24 x 109 and 2.27 x 109 s-1 cm3, respectively, and the corresponding trapping cross-sections were estimated to be 2.66 x 10-16, 2.14 x 10-16, 2.10 x 10-16 and 3.51 x 10-16 cm2. It was found to be very clear that the mean lifetime and S-parameter exhibited the same behaviour as a function of the degree of deformation, and that they saturated at the same degree of thickness reduction.

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INFLUENCE OF Mg CONTENT ON TRAPPING EFFICIENCY IN Al–Mg SYSTEM BY POSITRON ANNIHILATION SPECTROSCOPY

Surface Review and Letters ◽

10.1142/s0218625x06008451 ◽

2006 ◽

Vol 13 (04) ◽

pp. 485-488

Author(s):

EMAD BADAWI ◽

M. A. ABDEL-RAHMAN ◽

M. O. ABDELHAMED

Keyword(s):

Positron Annihilation ◽

Cross Section ◽

Positron Annihilation Spectroscopy ◽

Trapping Efficiency ◽

Doppler Broadening ◽

Deformation Degree ◽

S Parameter ◽

Mean Lifetime ◽

The Mean ◽

Mg Content

PLT and Doppler broadening S-parameter were used for Al – Mg alloy, namely 5005, 5051, 5052 and 5083. The trapping efficiency was estimated for the pervious alloys as 2.42 × 109, 2.29 × 109, 2.24 × 109 and 2.27 × 109 s -1 cm 3, respectively and the trapping cross-section was estimated to be as 2.66 × 10-16, 2.14 × 10-16, 2.10 × 10-16 and 3.51 × 10-16 cm 2, respectively. It is clear that the mean lifetime and S-parameter have the same behavior as a function of deformation degree and saturated at the same value of thickness reduction.

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Investigation of Oxidation Behaviors of Al-Mg Alloys with a Grain Refiner at High Temperature

Journal of Nanoelectronics and Optoelectronics ◽

10.1166/jno.2021.3020 ◽

2021 ◽

Vol 16 (7) ◽

pp. 1129-1133

Author(s):

Seong-Ho Ha ◽

Abdul Wahid Shah ◽

Bong-Hwan Kim ◽

Young-Ok Yoon ◽

Hyun-Kyu Lim ◽

...

Keyword(s):

High Temperature ◽

Cross Sections ◽

Master Alloy ◽

Mg Alloys ◽

Ambient Atmosphere ◽

Grain Refiner ◽

Long Duration ◽

The Matrix ◽

Al Mg Alloys ◽

Oxidation Behaviors

Studies to investigate the oxidation behavior of Al–Mg alloys with Al-5 mass%Ti-1 mass%B master alloy as a grain refiner at high temperature were conducted. The Scheil-Gulliver cooling calculation showed that, in 0.2 mass%Ti-inoculated alloy, TiAl3 was formed before the primary Al formation, which may act as a grain refiner. The optical microstructures showed a significant grain refinement after the addition of 0.2 mass%Ti using Al-5 mass%Ti-1 mass%B master alloy. Moreover, the oxidized cross-sections, throughout the oxidation time, show coarse and dark areas (regarded as oxide clusters), which were nonuniformly distributed in the matrix after oxidation at 500 °C under an ambient atmosphere. In addition, an accumulation of oxygen by diffusion for a long duration led to the growth of blisters after 50 h. At the oxidation temperature, Mg3Ti2Al18 was found to be only stable Ti-containing phase and possibly formed MgO by the interaction with the diffused oxygen.

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GRAIN SIZE IN CASTING AND WROUGHT Al-ALLOYS BY POSITRON LIFETIME TECHNIQUE

Surface Review and Letters ◽

10.1142/s0218625x05006925 ◽

2005 ◽

Vol 12 (02) ◽

pp. 197-202

Author(s):

M. A. ABDEL-RAHMAN ◽

R. M. ABDEL-LATIF ◽

M. S. ABDALLAH ◽

EMAD A. BADAWI

Keyword(s):

Grain Size ◽

Grain Boundaries ◽

Positron Lifetime ◽

Fortran Program ◽

Al Alloys ◽

Degree Of Deformation ◽

Mean Lifetime ◽

The Mean

Positron behavior at grain boundaries is characterized by their bulk diffusibility D, their bulk free lifetime τf and their trapped lifetime τt(τt > τf). AlSi 11.35 Mg 0.23, AlSi 10.9 Mg 0.17 Sr 0.06, 7075 and 2024 alloys have been homogenized at 673 K for 12 hours. The mean lifetime, as (indirectly) measured at various strains (degrees of deformation), show a good fitting with a FORTRAN program. τf and τt for the above materials are shown as: (187.3 ± 0.10, 229.7 ± 0.10), (198.0 ± 0.10, 230.3 ± 0.10), (205.4 ± 0.05, 213.4 ± 0.06) and (197.1 ± 0.55, 215.2 ± 0.57) Ps respectively. The mean lifetime was found to vary exponentially with the degree of deformation.

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STUDY OF TRAPPING RATE AND DEFECT DENSITY IN AlSi11.35Mg0.23 BY POSITRON ANNIHILATION TECHNIQUE

Surface Review and Letters ◽

10.1142/s0218625x0400630x ◽

2004 ◽

Vol 11 (04n05) ◽

pp. 427-432 ◽

Cited By ~ 5

Author(s):

M. A. ABDEL-RAHMAN ◽

M. S. ABDALLAH ◽

EMAD A. BADAWI

Keyword(s):

Positron Annihilation ◽

Defect Density ◽

Defect Concentration ◽

Thickness Reduction ◽

Trapping Rate ◽

Positron Annihilation Lifetime ◽

Maximum Value ◽

Mean Lifetime ◽

The Mean

The measurements of Positron Annihilation Lifetime Technique (PALT) have been performed on AlSi 11.35 Mg 0.23 Alloys. It has been shown that positrons can become trapped at imperfect locations in solids and their mean lifetime can be influenced by changes in the concentration of such defects. No change has been observed in the mean lifetime values at the saturation of defect concentration. The trapping rates of positrons can be determined for thickness reduction up to 11% for dislocation. The concentration of defect (ρ') range varies from 8.65×1015 to 2.35×1018 cm -3 up to the maximum value of strain (ε) 0.23.

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POSITRON ANNIHILATION AND XRD FOR DETECTING Al ALLOYS (50XX)

Surface Review and Letters ◽

10.1142/s0218625x04006104 ◽

2004 ◽

Vol 11 (02) ◽

pp. 167-171 ◽

Cited By ~ 5

Author(s):

EMAD BADAWI

Keyword(s):

Positron Annihilation ◽

Al Alloys ◽

Preferred Orientation ◽

Doppler Broadening ◽

Degree Of Deformation ◽

Mean Lifetime ◽

Mg Content

The positron annihilation parameter (mean lifetime) increases with increasing Mg contents for annealed and quenched samples (50 XX ). Positron parameter τ, s (Doppler broadening) increase with increasing Q.T for the same (50 XX ). The preferred orientation is one of the most important parameters that can be observed by XRD for materials, for such measurements in our observation: the dependence of the preferred orientation on the Mg content, the dependence of the preferred orientation on the Q.T, and the dependence of the preferred orientation on the degree of deformation.

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Temperature Dependences in the O + OH → O2 + H Reaction. Quasiclassical Trajectory Calculation

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19930234 ◽

1993 ◽

Vol 58 (2) ◽

pp. 234-243 ◽

Cited By ~ 4

Author(s):

Viliam Klimo ◽

Martina Bittererová ◽

Stanislav Biskupič ◽

Ján Urban ◽

Miroslav Micov

Keyword(s):

Temperature Dependence ◽

Energy Surface ◽

Analytical Form ◽

Mean Values ◽

Quantum Numbers ◽

Mean Lifetime ◽

Temperature Dependences ◽

Quasiclassical Trajectory Calculation ◽

The Mean ◽

Combustion Processes

The reaction O + OH → O2 + H in conditions of combustion of hydrocarbons and polymers was modelled by using the method of quasiclassical trajectories. The potential energy surface was determined by the multiconfiguration interaction method and fitted with the analytical form of the extended LEPS function. Attention was paid to the mean values of the vibrational and rotational quantum numbers of O2 molecules and their temperature dependence. The temperature dependence of the mean lifetime of the OOH collision complex was also examined. The calculated rate constants were analyzed and compared with the experimental data over the temperature region of the combustion processes.

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