Detecting Defects in Aircraft Materials by Nuclear Technique (Pas)

Abdallah

Hassan

et al. 2008

DDF

Positron annihilation lifetime is one of the most important nuclear techniques, used to study the isochronal and isothermal annealing in one of the most important engineering aluminum alloys which is 2024 alloy. Samples of 25 % deformation have been used for these studies. Two recovery stages during the isochronal annealing [1] were observed which were ascribed to the recovery of point defects and dislocations introduced by the deformation. The isothermal annealing measurements were performed at 583, 603, 623 and 643 K from which the activation energy obtained was 1.24 ± 0.08 eV.

“…A fast-fast coincidence technique, described elsewhere [9,10], was used in this study. The resolution of the system is 290 ps as measured by using the coincidence as given by 60 Co.…”

Section: Methodsmentioning

confidence: 99%

Activation Enthalpy of Dislocation Migration in Aircraft (Aerospace) (2024) Alloy by Positron Spectroscopy

Abdallah

Hassan

et al. 2008

DDF

“…A fast-fast coincidence technique, described elsewhere [9,10], was used in this study. The resolution of the system is 290ps as measured by using the coincidence as given by 60 Co.…”

Section: Experimental 21 Positron Annihilation Lifetime Techniquementioning

confidence: 99%

Probing the Activation Migration Enthalpies of Dislocations in 2024 Aircraft Material Using Nuclear and Electrical Techniques

Kamel

Refeay

et al. 2011

DDF

Positron annihilation lifetime (PAL) measurement is one of the most important nuclear techniques used in materials science. Electrical measurements are also used in materials science. Both PAL and electrical measurements were used here to determine the activation energy of migration of dislocations in one of the most important engineering aluminum alloys: 2024. Samples of 25% deformed (thickness reduction) material have been used for these studies. The isothermal annealing measurements were performed at 583, 603, 623 and 643K for both techniques. The activation energy of migration of the dislocation was found to be equal to 1.24 ± 0.08eV by using PAL measurements and to 1.35 ± 0.01eV by using the electrical technique.

“…A fast-fast coincidence technique, described elsewhere [1,10], was used in this study. The resolution of the system is 290 ps as measured by using the coincidence as given by 60 Co.…”

Section: Positron Annihilation Lifetime Techniquementioning

confidence: 99%

“…Since 7075 alloy has a good properties and important application it has become the interest of the study. Positron annihilation lifetime is chosen as a tool (method) to study this alloy [1]. Positron annihilation spectroscopy is widely used in studying the electronic structure as well as the crystal lattice defects in metals [2].…”

Section: Introductionmentioning

confidence: 99%

Isochronal and Isothermal Annealing of Wrought Aluminum Alloy

Kamel

Refeay

et al. 2011

DDF

Positron annihilation lifetime (PAL) is one of the most important nuclear techniques used in material science. Electrical measurements are also used in material science. Samples of 25 % deformation have been used for these studies. Both positron annihilation lifetime and electrical measurements were used to determined the activation energy of migration the dislocation in 7075 alloy. The isothermal annealing measurements were performed at 643, 663, 683 and 703 K. The activation energy of migration the dislocation are obtained as 1.35 ± 0.16 eV and 1.25 ± 0.05 eV for positron annihilation lifetime and electrical techniques respectively.