Structure identification and site preference of Ta and Cd in Ti–Pd alloys: A first-principle study

By means of a density functional theory approach, we studied the electric field gradients (EFG) in Ta and Cd-doped Ti–Pd intermetallics. Our results confirmed the previous experimental findings that the TiPd2 low-temperature structure is orthorhombic and established that Ta substitutes for Ti in this structure. The temperature increase above 650 K changes the Ta impurity position in the lattice. Similar changes for the Cd doped system were not confirmed, as Cd is most likely to occupy Pd lattice sites in both low and high-temperature phases. In the case of TiPd, our calculations suggested that Ta substitutes for Ti in the low-temperature phase, while Cd probably can substitute on both Ti and Pd crystallographic sites.

► We calculated electric field gradients in Ta and Cd doped TiPd and TiPd2.
► Ta substitutes for Ti in the low-temperature orthorhombic TiPd2 structure.
► Above 650 K in TiPd2 Ta replaces Pd instead of Ti.
► In the low-temperature TiPd phase Ta changes Ti, while Cd prefers Pd site.