Structural, elastic and thermodynamic properties of iron carbide Fe7C3 phases: an ab initio study

• T. Chihi^a, 
• A. Bouhemadou^b, 
• M. Reffas^a, 
• R. Khenata^c, 
• M.A. Ghebouli^d, , , 
• B. Ghebouli^e, 
• L. Louail^d

• 
  
• ^a Department of Physics, Faculty of Science, University of Setif 1, 19000 Setif, Algeria
• ^b Laboratory for Developing New Materials and their Characterization, Department of Physics, Faculty of Science, University of Setif 1, 19000 Setif, Algeria
• ^c Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, 29000 Mascara, Algeria
• ^d Faculty of Technology, Mohamed Boudiaf University, M'sila, Algeria
• ^e Laboratory of Surface and Interface Studies of Solid Materials, Department of Physics, Faculty of Science, Setif University 1, Setif 19000, Algeria

Received 10 May 2016, Revised 28 October 2016, Accepted 17 December 2016, Available online 23 March 2017

Abstract

Using ab initio spin-polarized density functional theory calculations, the structural, elastic and thermodynamic properties of the orthorhombic and hexagonal phases of the iron carbide Fe₇C₃ were investigated. The calculated ground-state lattice parameters are in good agreement with the available corresponding theoretical and experimental data. The single-crystal and polycrystalline aggregate elastic constants, sound velocities, Debye temperature, brittle/ductile character and elastic anisotropy have been estimated. The calculated bulk modulus values of both considered phases are very close and are approximately equal to 262 GPa, which classifies the title compounds among the hard materials. The temperature and pressure dependencies of the unit-cell volume, bulk modulus, volume thermal expansion coefficient, isochoric and isobaric heat capacity, and Debye temperature were investigated using the quasi-harmonic Debye model.

To download the article click on the link below:

http://www.sciencedirect.com.sci-hub.cc/science/article/pii/S0577907316302222