Open AccessInfluence of carbon on energetics, electronic structure, and mechanical properties of TiAl alloys
Author(s) -
Dominik Legut,
Jürgen Spitaler,
P. Pavone,
Claudia Draxl
Publication year - 2021
Publication title -
new journal of physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.584
H-Index - 190
ISSN - 1367-2630
DOI - 10.1088/1367-2630/ac0c98
Subject(s) - octahedron , carbon fibers , ductility (earth science) , phase (matter) , thermodynamics , stoichiometry , electronic structure , alloy , materials science , enthalpy , anisotropy , crystallography , condensed matter physics , physics , crystal structure , chemistry , composite material , composite number , creep , quantum mechanics
We present first-principles calculations of carbon-doped TiAl alloys. The effect of carbon on the structural, electronic, and elastic behavior of the γ phase ( L 1 0 structure) of TiAl is investigated. The calculated enthalpy of formation at zero temperature indicates that carbon atoms favor to occupy rather interstitial than substitutional positions. The computed solubility of carbon in the stoichiometric γ phase is very low, in agreement with experimental findings. However, it is significantly enhanced for the Ti-rich alloy and when located inside Ti 6 octahedra. Mechanical properties such as Cauchy pressure, elastic anisotropy, Young’s modulus, as well as Pugh and Poisson ratios of stoichiometric and off-stoichiometric compositions are analyzed as a function of carbon concentration and its location. As a general trend, we obtain that below a concentration of 3 at.%, carbon plays a minor role in changing the ductile behavior of γ -TiAl. A slight increase in ductility is found in the Ti-rich γα phase if either located in the Ti-plane (Ti 4 Al 2 octahedral site) or in a Ti 6 octahedra.