Vacancy Formation in Fe-Al of B2 and DO_3 Alloys

• Authors: J. Kansy , A. Hanc , D. Giebel , M. Jabłońska
• Languages of publication: EN

Abstracts

EN

The positron lifetime spectroscopy is employed to study vacancy formation in intermetallic phases of DO_3 and B2 structures from Fe-Al system as a function of Al concentration, ternary additive (Cr) and their thermal treatment. Lifetime spectra were fitted en block by a simple trapping model encoded directly to the software (computer program LT-9). In the investigated range of Al concentration (28, 38, 42, and 45 at%) only two types of defects are found. In DO_3 region a single type of defects (characterized by positron lifetime τ_1=170±2 ps) is detected and indicated as vacancies in the Fe sublattice (V_{Fe}). In B2 region a small amount of an additional type of defects (characterized by positron lifetime τ_2=214±13 ps) appears. Supposedly, these are vacancies in Al sublattice (V_{Al}). For Fe28Al and Fe28Al5Cr samples changes in V_{Fe} concentration are determined as a function of the sample composition, annealing time at 1000°C and quenching the samples to air and oil. The defect concentration increases with increase in Al content. For FeAl with Al above 38 at%, the total concentration of defects is so high that positrons are exclusively trapped by defects. Therefore the concentrations V_{Al} and V_{Fe} cannot be determined separately. However, the ratio of V_{Al} concentration to V_{Fe} concentration is estimated as a function of Al content.

Keywords

EN

78.70.Bj; 71.55.Ak

Discipline

• 78.70.Bj: Positron annihilation(for positron states, see 71.60.+z in electronic structure of bulk materials; for positronium chemistry, see 82.30.Gg in physical chemistry and chemical physics)
• 71.55.Ak: Metals, semimetals, and alloys

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2008
• Volume: 113
• Issue: 5
• Pages: 1409-1415

Dates

published

2008-05

received

2007-09-03

Contributors

author

J. Kansy

• Institute of Materials Science, University of Silesia, Bankowa 12, 40-007 Katowice, Poland

author

A. Hanc

• Institute of Materials Science, University of Silesia, Bankowa 12, 40-007 Katowice, Poland

author

D. Giebel

• Institute of Materials Science, University of Silesia, Bankowa 12, 40-007 Katowice, Poland

author

M. Jabłońska

• Institute of Materials Science, Silesian Technical University, Krasińskiego 8, 40-019 Katowice, Poland

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Identifiers

DOI

10.12693/APhysPolA.113.1409