Theoretical investigation on elastic and thermal properties of layered ternary ceramic-Ti4AlN2.89 under high pressure

Abstract

Using pseudopotential plane-waves method, we calculated the structural, elastic properties and hardness for layered ternary ceramic Ti4AlN2.89 in the pressure range from 0 to 200 GPa. The elastic properties were derived to discuss the stability and bonding composition of Ti4AlN2.89 under high pressure. It is observed that this crystal is stable in our studied pressure range, and there are four typical bonds in Ti4AlN2.89. 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 Ti4AlN2.89 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 Ti4AlN2.89 increases as the pressure is increased. What’s more, by calculating the Debye temperatures under high pressure, we found the melting point of Ti4AlN2.89 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 Ti4AlN2.89 might be improved at a higher pressure.