Phase stability and electronic properties of Cubic PtY, Pt2Y, Pt3Y, PtSc Pt3Sc and orthorhombic PtY, PtY2, PtY3 PtSc2 platinum-based alloys: A first principles DFT study

Ab initio calculations based on density functional theory (DFT) were performed to investigate the structural, mechanical, vibrational, and electronic properties of orthorhombic phases of PtY, PtY 2 , PtY 3 , and PtSc 2 , as well as cubic forms of PtY, Pt 2 Y, and PtSc platinum-based alloys. This study presents the first computational investigation of these specific compounds. Using the generalized gradient approximation (GGA), all compounds were found to exhibit negative formation energies, confirming their thermodynamic stability. Elastic constant calculations demonstrate that the alloys satisfy the Born mechanical stability criteria and exhibit ductile behavior, with PtSc 2 displaying the highest ductility (B/G ratio of 3.24) and Pt 2 Y the lowest (2.21). All compounds possess high melting temperatures (Tm) exceeding 1000 K, with Pt 3 Sc (2401 K), Pt 3 Y (2175 K), Pt 2 Y (2103 K), and PtSc (1850 K) identified as the most thermally stable. Phonon spectra reveal no imaginary (soft) modes, confirming the dynamical stability of all phases. Electronic analysis indicates metallic conductivity due to valence–conduction band overlap at the Fermi level (E F ). Notably, cubic PtY and PtSc, and orthorhombic PtY, exhibit the lowest density of states at the Fermi level (N(E F )), suggesting enhanced electronic stability. Thermal analysis shows that Pt 3 Sc (303.64 K) and Pt 2 Y (286.31 K) have the highest Debye temperatures, whereas PtY 2 and PtY 3 exhibit the lowest. Minimum thermal conductivity results highlight PtY 3 and PtY 2 as the least conductive, identifying them as promising candidates for thermal barrier coatings. Finally, the study suggests that the concentrations of Sc, Y, and Pt are the primary factors governing the observed trends in stability and stiffness. These macroscopic properties exhibit a clear interdependence with the underlying electronic structure, specifically the density of states at the Fermi level, N(E F ). • First-time DFT study of PtY, Pt2Y, PtSc (cubic) and PtY, PtY2, PtY3, PtSc2 (orthorhombic) phases. • All alloys are stable conductors with ductile mechanical behavior and high melting temperatures. • These alloys show promise for high-temperature structural applications in aerospace and turbines.