Early stages of decomposition in iron-carbon and iron-nitrogen martensites: Diffraction analysis using synchrotron radiation

Journal Article · Wed Sep 01 04:00:00 EDT 1993 · Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States)

DOI:https://doi.org/10.1007/BF02666331· OSTI ID:6269569

Van Genderen, M J; Boettger, A; Mittemeijer, E J ^[1]; Cernik, R J ^[2]

---

1. Delft Univ. of Technology (Netherlands). Lab. of Metallurgy
2. Science and Engineering Research Council Daresbury Lab., Warrington (United Kingdom)

The early stages of decomposition of iron-carbon and iron-nitrogen martensites were studied by means of diffraction analysis. After aging at room temperature (RT) for 3.5 years and after tempering at 405 K for 1 hour, [var epsilon]/[eta] transition carbide reflections but no [alpha][double prime]-type (superstructure) reflections were detected for FeC martensites. However, for FeN martensites, the [alpha][double prime] superstructure reflections were observed on aging at RT for 3.5 years and on tempering at 405 K for 1.5 hour. For short aging times at RT (up to 60 hours), [alpha][double prime] reflections (not of the superstructure type) were observed for FeN martensites. Upon tempering, changes in the [alpha][double prime] crystal structure occur, which were discussed in terms of annihilation of structural vacancies on the nitrogen sublattice and stress relaxation. In the diffraction pattern recorded from FeC martensite (for short aging times at RT), weak reflections occurred which could not be identified conclusively yet and which disappeared after tempering for 1 hour at 405 K.

• OSTI ID: 6269569
• Journal Information: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States), Journal Name: Metallurgical Transactions, A (Physical Metallurgy and Materials Science); (United States) Vol. 24:9; ISSN 0360-2133; ISSN MTTABN
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
AGING
ALLOYS
CARBIDES
CARBON ADDITIONS
CARBON COMPOUNDS
CHEMICAL REACTIONS
COHERENT SCATTERING
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DECOMPOSITION
DIFFRACTION
HEAT TREATMENTS
IRON ALLOYS
IRON BASE ALLOYS
IRON CARBIDES
IRON COMPOUNDS
IRON NITRIDES
MARTENSITE
MICROSTRUCTURE
NITRIDES
NITROGEN COMPOUNDS
PHASE TRANSFORMATIONS
PNICTIDES
POINT DEFECTS
RELAXATION
SCATTERING
STEELS
STRESS RELAXATION
TEMPERING
TRANSITION ELEMENT COMPOUNDS
VACANCIES
X-RAY DIFFRACTION