Electronic structures, elastic properties, and minimum thermal conductivities of cermet M3AlN

• We calculated three anti-perovskite cermets with first-principles theory.
• We illustrated 3D Young modulus and found the anomalous anisotropy.
• We explained the anomaly and calculated the minimum thermal conductivities.

The electronic structures and elastic anisotropies of cubic Ti3AlN, Zr3AlN, and Hf3AlN are investigated by pseudopotential plane-wave method based on density functional theory. At the Fermi level, the electronic structures of these compounds are successive with no energy gap between conduct and valence bands, and exhibit metallicity in ground states. In valence band of each partial density of states, the different orbital electrons indicate interaction of corresponding atoms. In addition, the anisotropy of Hf3AlN is found to be significantly different from that of Ti3AlN and Zr3AlN, which involve the differences in the bonding strength. It is notable that Hf3AlN is a desired thermal barrier material with the lowest thermal conductivity at high temperature among the three compounds.

1.Young׳s moduli of anti-perovskite Ti3AlN, Zr3AlN, and Hf3AlN in full space.2.Electron density differences on crystal planes (1 0 0), (2 0 0), and (1 1 0) of anti-perovskite Zr3AlN.Figure optionsDownload as PowerPoint slide