Interaction between titanium and nitrogen atoms in solid solution of ferrous alloys

• Published in: Acta metallurgica et materialia 1993-05, Vol.41 (5), p.1625-1632
• Main Authors: Hu, X.F., Ge, Q.L., Wu, Z.L.
• Format: Article
• Language: English
• Subjects: 360102 - Metals & Alloys- Structure & Phase Studies; 360103 - Metals & Alloys- Mechanical Properties; 360202 - Ceramics, Cermets, & Refractories- Structure & Phase Studies; 360203 - Ceramics, Cermets, & Refractories- Mechanical Properties; ACTIVATION ENERGY; ALLOYS; Applied sciences; ATOM TRANSPORT; Condensed matter: structure, mechanical and thermal properties; ENERGY; Exact sciences and technology; FRICTION; INTERNAL FRICTION; IRON ALLOYS; MATERIALS SCIENCE; Metals. Metallurgy; NEUTRAL-PARTICLE TRANSPORT; NITRIDES; NITROGEN COMPOUNDS; Physics; PNICTIDES; RADIATION TRANSPORT; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; TITANIUM COMPOUNDS; TITANIUM NITRIDES; TRANSITION ELEMENT COMPOUNDS
• ISSN: 0956-7151; 1873-2879
• DOI: 10.1016/0956-7151(93)90271-S

Fe-1.08Ti alloy nitrided at 400°C to a nitrogen content corresponding to N/Ti < 1 produces only two peaks at 220°C (P II) and 390°C (P I) respectively in the internal friction spectrum. The 390°C peak is attributed to the diffusion jump of the nitrogen atom in a random Ti-N dipole from the nearest interstice to the next to the titanium atom. Activation energy of this peak is 1.88eV, higher by 1.05eV than that for the normal Snoek peak induced by rotation of Fe-N dipoles. This raise in potential barrier originates from the strong chemical affinity of nitrogen to titanium atom in close proximity. Evidences are given to demonstrate that the 390°C peak is generated by a Debye type relaxation of individual nitrogen atoms. The 220°C peak decomposes upon annealing to two subpeaks P′ II (230°C) and P″ (180°C) having activation energy 1.40 and 1.24 eV respectively. These peaks are generated by a synchronous jump of two types of N-N pairs different in binding energies.