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Pressure–composition phase diagram of Ti– C from first principles
Author(s) -
Jiang Chao,
Jiang Wensen
Publication year - 2014
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201350209
Subject(s) - tetragonal crystal system , phase diagram , carbide , ab initio , materials science , phase (matter) , titanium , ab initio quantum chemistry methods , high pressure , crystallography , thermodynamics , chemistry , metallurgy , crystal structure , physics , molecule , organic chemistry
In this paper, we report a theoretical prediction of the zero‐temperature pressure–composition phase diagram for the binary Ti–C system using ab initio evolutionary methodology. Our ground state search successfully identifies the known stable Ti 2 C, Ti 3 C 2 , Ti 6 C 5 , and TiC structures at 0 GPa. Our study uncovers two new titanium carbides that are thermodynamically stable at high pressures: tetragonal Ti 2 C with I4/m symmetry and tetragonal Ti 3 C 2 with P4/mbm symmetry. Both carbides are quenchable to ambient pressure and remain mechanically stable, and are potential candidates for hard materials. The I4/m and P4/mbm structures are also expected to be stable in the isoelectronic Zr–C and Hf–C systems at high pressures. Experimental synthesis of these novel carbides will be of great interest.