Thermodynamics and long-range order of nitrogen in {gamma}{prime}-Fe{sub 4}N{sub 1{minus}x}
Journal Article
·
· Metallurgical Transactions, A
OSTI ID:250732
- Delft Univ. of Technology (Netherlands). Lab. of Materials Science
Models are given for the description of the chemical potential of nitrogen in {gamma}{prime}-Fe{sub 4}N{sub 1{minus}x}. In previous work, {gamma}{prime}-Fe{sub 4}N{sub 1{minus}x} was treated as a (sub)regular solution, thereby assuming that the N atoms are distributed randomly on the sites of their own sublattice. However, in {gamma}{prime}-Fe{sub 4}N{sub 1{minus}x}, long-range ordering occurs of the N atoms over the sites of their own sublattice. Then, the expression for the configurational entropy should account for the occurrence of ordering. In the present article, the descriptions adopted and tested for {gamma}{prime}-Fe{sub 4}N{sub 1{minus}x} are based on a Langmuir-type approach, the Wagner-Schottky (WS) approach, and the Gorsky-Bragg-Williams (GBW) approach. Application of the various models to data of nitrogen-absorption isotherms for the {gamma}{prime} iron-nitride phase shows that the subregular solution concept fails to describe the experimental data satisfactorily, whereas a very good agreement between theory and experiment is obtained for the WS and GBW approaches. It is shown that, in particular, accounting for the occupation of disorder (octahedral) sites by N atoms is necessary to obtain an accurate description of the chemical potential of nitrogen in {gamma}{prime}-Fe{sub 4}N{sub 1{minus}x}.
- OSTI ID:
- 250732
- Journal Information:
- Metallurgical Transactions, A, Journal Name: Metallurgical Transactions, A Journal Issue: 4 Vol. 27; ISSN 0360-2133; ISSN MTTABN
- Country of Publication:
- United States
- Language:
- English
Similar Records
An evaluation of the Fe-N phase diagram considering long-range order of N atoms in {gamma}{prime}-Fe{sub 4}N{sub 1{minus}x} and {var_epsilon}-Fe{sub 2}N{sub 1{minus}z}
Thermodynamics and long-range order of interstitials in an h.c.p. lattice: Nitrogen in {var_epsilon}-Fe{sub 2}N{sub 1{minus}z}
Thermodynamics and long-range order of interstitials in a hexagonal close-packed lattice
Journal Article
·
Sun Mar 31 23:00:00 EST 1996
· Metallurgical Transactions, A
·
OSTI ID:250733
Thermodynamics and long-range order of interstitials in an h.c.p. lattice: Nitrogen in {var_epsilon}-Fe{sub 2}N{sub 1{minus}z}
Journal Article
·
Thu May 01 00:00:00 EDT 1997
· Acta Materialia
·
OSTI ID:509139
Thermodynamics and long-range order of interstitials in a hexagonal close-packed lattice
Journal Article
·
Wed Nov 30 23:00:00 EST 1994
· Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)
·
OSTI ID:6875108