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Calculations of charge transfer in Mg-and Al-transition metal alloys using the Auger parameter

✍ Scribed by Diplas, S.; Shao, G.; Tsakiropoulos, P.; Watts, J. F.; Matthew, J. A. D.


Publisher
John Wiley and Sons
Year
2000
Tongue
English
Weight
247 KB
Volume
29
Category
Article
ISSN
0142-2421

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✦ Synopsis


Conventional and high-energy x-ray photoelectron spectroscopy (XPS) with Al Ka and Cr Kb radiation, respectively, were used to calculate the Auger parameters of the elements in a vapour-deposited Mg-8.9 at.% V alloy and in as-cast V-50 at.% Al and Nb-17 at.% Al alloys. Analysis of variations in the Auger parameters of the elements of interest between unalloyed and alloyed conditions were used to calculate values of charge transfer, occurring upon alloying, using the model developed by Thomas and Weightman. These values were used to investigate the electronic changes that take place upon alloying Mg with V and Al with V and Nb. The results were related to the general alloying behaviour of the Mg-V system as well as to thermodynamic predictions and the microstructures of the other two alloys. An attempt has been made to understand the metallurgical significance of charge transfer in terms of the tendency for ordering or disordering of solid solutions. The ordering tendency in the Nb-17 at.% Al alloy, shown by thermodynamic modelling and microstructural studies, was attributed to substantial electron transfer from Al to Nb. The small charge transfer from Al to V in the V-50 at.% Al alloy was attributed to the lack of ordering in this system.