A new theoretical superstoichiometric hard $TiN_x$ crystal
  In this article we present the application of a \textit{ab initio} methodology to design new hard materials with crystal behavior. In special, we applied this methodology in the search of new materials of the $TiN_x$ family. This search will find a set of structures super-stoichiometrics $Ti_3N_4$ and properties of the candidate to greatest hardness are evaluated. Hardness model used in this work is described by Anton\'in Simunek and Jir\'i Vack\'ar (2006). 
Edward Y. Villegas and Mario V\'elez
cond-mat.mtrl-sci cond-mat.mes-hall