Electronic structure and phase equilibria in ternary substitutional alloys

Abstract

\This is an informal r w L intended primarily for internal or dismbytion. The opiniw nand conclusions stated are those of the aut or may not be those of I ! ! Laboratory. The formalism is applied to the study of bcc-based ternar? Zr-Ru-Pd alloys which are promising candidates for medikal implant device applications. Using the enersetics obtained with the aforementioned scheme, we apply the cluster-variation method to study phase equilibria for particular pseudo-binary alloys, and show that the results are consistent with the observed behavior of tlie electronic specific heat coefficient with composition for the Zro.5(Ru,Pd)0.5 system.

Real-space tight-binding approach to stability and order in substitutional multicomponent alloys

“…These alloys belong to a class of materials which exhibit interesting properties for biocompatible implant device applications. 25 To describe their electronic structure properties, the Slater-Koster ͑SK͒ parameters which enter the TB Hamiltonian have been extracted from TB LMTO calculations as described in Ref. 25.…”

“…26 As in Ref. 25, the SK parameters for the pure metals are assumed to vary with the interatomic distance d, according to…”

“…These parameters are given in Table I for Rh, and in Table I of Ref. 25 for Zr and Ru. For a particular alloy, the SK parameters have been approximated according to…”

“…25 In the latter case, the average Green function was obtained after integration in reciprocal space over the first Brillouin zone with 240 special k points. 27 Figure 9 shows the DOS of bcc-based Zr 0.5 Rh 0.5 obtained with both approaches.…”

“…Only the sites of this latter sublattice will be ''dressed'' with semilinear chains ͑one per orbital͒ which represent the self-energies ͑one per orbital͒, and the CPA equations for this pseudobinary alloy can be solved in the same way they are for the binary case. For comparison, a similar calculation can be performed with a k-space approach, 25 but now the integration has to be done in the Brillouin zone of the simple cubic lattice ͑in the present case, 816 special k points 27 have been used͒. From Fig.…”