ELASTIC-CONSTANTS AND PLANAR FAULT ENERGIES OF TI3AL, AND INTERFACIAL ENERGIES AT THE TI3AL/TIAL INTERFACE BY FIRST-PRINCIPLES CALCULATIONS

We have presented results of first-principles calculations of the elastic constants of Ti3Al, and the planar fault energies in Ti3Al and at the TiAl Ti3Al interfaces. Similar to those found in Ti, the bonding in Ti3Al is dominated by the multi-centered bonding interactions, but is enhanced by the presence of Al atoms. The bonding enhancement is manifested in stiffer elastic moduli and considerably high APB energies (even in the case where the nearest-neighbor coordination of atoms is not altered by the presence of APB, i.e., APB-I on the prism plane). The APB and CSF energies are reduced at the TiAl Ti3Al interface from those of either constituent phase, since the long-range bonding interactions are disrupted at the interface. © 1995.