On the use of Positron Annihilation Spectroscopy in the Study of a Nonuniform Spatial Distribution of Metallurgical Defects

1986 ◽  
Vol 82 ◽  
Author(s):  
James P. Schaffer

ABSTRACTMost of the Interpretation of positron annihilation results to date have been done within the context of the simple trapping model which assumes a uniform spatial distribution of defects within the specimen examined. While this assumption is often justifiable there are numerous metallurgical defect configurations which are markedly nonuniform. In this work some of the appropriate trapping models which have previously appeared in the literature will be briefly reviewed. Additional models which are currently being developed will be presented and the series of experiments which are being used to test the trapping models will be described.

2005 ◽  
Vol 482 ◽  
pp. 207-210 ◽  
Author(s):  
Jakub Čížek ◽  
Ivan Procházka ◽  
Bohumil Smola ◽  
Ivana Stulíková ◽  
Radomír Kužel ◽  
...  

In the present work, positron annihilation spectroscopy (PAS) is employed for microstructure investigations of various ultra fine grained (UFG) metals (Cu, Ni, Fe) prepared by severe plastic deformation (SPD), namely high-pressure torsion (HPT) and equal channel angular pressing (ECAP). Generally, UFG metals prepared using both the techniques exhibit two kinds of defects introduced by SPD: dislocations and small microvoids. The size of the microvoids is determined from the PAS data. Significantly larger microvoids are found in HPT deformed Fe and Ni compared to HPT deformed Cu. The microstructure of UFG Cu prepared by HPT and ECAP is compared and the spatial distribution of defects in UFG Cu samples is characterized. In addition, the microstructure of a pure UFG Cu prepared by HPT and HPT deformed Cu+Al2O3 nanocomposite (GlidCop) is compared.


2009 ◽  
Vol 293 ◽  
pp. 19-26
Author(s):  
Emad A. Badawi ◽  
M.A. Abdel-Rahman ◽  
E.M. Hassen ◽  
M. Abdel-Rahman ◽  
M.O. Abdel-Hamed

A description of positron annihilation spectroscopy (PAS) in solids is given in terms of a trapping model. Data are presented for a commercial AA1050 dilute alloy ingot, and fitted to a model allowing presentation in the form of Arrhenius plots. From whence the value of the activation enthalpy, , for thermal vacancies obtained by PAS for AlFeSi is found to be 0.860.18eV.


2009 ◽  
Vol 106 (1) ◽  
pp. 013524 ◽  
Author(s):  
L. Kilanski ◽  
A. Zubiaga ◽  
F. Tuomisto ◽  
W. Dobrowolski ◽  
V. Domukhovski ◽  
...  

2016 ◽  
Vol 132 ◽  
pp. 03014
Author(s):  
E.V. Ahmanova ◽  
M.K. Eseev ◽  
A.G. Kobets ◽  
I.N. Meshkov ◽  
O.S. Orlov ◽  
...  

2006 ◽  
Vol 73 (19) ◽  
Author(s):  
S. Hautakangas ◽  
I. Makkonen ◽  
V. Ranki ◽  
M. J. Puska ◽  
K. Saarinen ◽  
...  

2014 ◽  
Vol 115 ◽  
pp. 47-50 ◽  
Author(s):  
Diána Hegyesi ◽  
Károly Süvegh ◽  
András Kelemen ◽  
Klára Pintye-Hódi ◽  
Géza Regdon

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