Theoretical investigation on elastic and thermal properties of layered ternary ceramic-Ti₄AlN_2.89 under high pressure

Using pseudopotential plane-waves method, we calculated the structural, elastic properties and hardness for layered ternary ceramic Ti 4 AlN 2.89 in the pressure range from 0 to 200 GPa. The elastic properties were derived to discuss the stability and bonding composition of Ti 4 AlN 2.89 under high pressure. It is observed that this crystal is stable in our studied pressure range, and there are four typical bonds in Ti 4 AlN 2.89 . They are Ti-N bonds, Ti-Ti, Al-Al and Ti-Al bonds, and Ti-N bonds are much stronger than Ti-Ti, Al-Al and Ti-Al bonds. In addition, we investigated the bond stiffness for Ti 4 AlN 2.89 under high pressure and found its damage tolerance and fracture toughness is improved at high pressure. Besides, we employed a semiempirical method considering the role of metallic components to evaluate the hardness of this compound at different pressures. Results showed that the Vickers hardness of Ti 4 AlN 2.89 increases as the pressure is increased. What’s more, by calculating the Debye temperatures under high pressure, we found the melting point of Ti 4 AlN 2.89 increases as the pressure is increasing. In a word, combined the results of mechanical properties with hardness and Debye temperature, we got the conclusion that the performance of Ti 4 AlN 2.89 might be improved at a higher pressure.