MOSSBAUER EFFECT IN IRON-CARBON AND IRON-NITROGEN ALLOYS.
Abstract
Interstitial solid solutions of carbon and nitrogen in iron were analyzed by Mossbauer spectroscopy. In both allotropic forms, austenite (gamma) and martensite (alpha), electric quadrupole effects were observed, arising from a repopulation of electrons among the d-orbitals of iron atoms adjacent to the interstitial atoms. In carbon austenite, the quadrupole effect of e sq qQ/2 = 0.625 mm/sec for iron atoms which are first neighbors of carbon atoms. In nitrogen-austenite, the quadrupole effects are smaller but an appreciable positive isomer shift is observed for iron atoms which are first neighbors of nitrogen atoms. This suggests that these iron atoms have more d-electrons due to some covalent bonding with nitrogen as exists in the isomorphous Fe4N phase. Carbon shows a positive and nitrogen a negative ion behavior in both martensite and in austenite. The c-axis is a direction of difficult magnetization in both Fe-C and Fe-N martensites.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 20, 1966
- Accession Number
- AD0633725
Entities
People
- P. M. Gielen
- Roy Kaplow
Organizations
- Massachusetts Institute of Technology