Tungsten-induced lattice distortion and fault-energy modulation in Pt-W solid solutions: A first-principles study

Tungsten (W) alloying is an effective strategy for improving the high-temperature strength and stability of Pt-based solid-solution alloys. Yet, the atomistic role of W in local bonding and fault-energy modulation remains insufficiently understood. Here, density-functional theory (DFT) calculations were performed to investigate Pt– x W ( x = 0-10 wt%) solid solutions, focusing on their structural stability, electronic structure, elastic properties, thermal behavior, and generalized stacking-fault energy (GSFE). The results show that increasing the W content induces a pronounced local lattice distortion and strengthens local bonding through Pt-d/W-d electronic hybridization, which reconfigures the electronic environment. Increasing the W content tends to increase the elastic stiffness, mechanical anisotropy, and Debye temperature of Pt, and to lower the thermal expansion coefficient. The GSFE calculations show that the addition of W significantly increases the unstable stacking-fault energy and Peierls stress of Pt and decreases the intrinsic stacking-fault energy. These findings suggest that the W-induced strengthening in Pt stems from the synergistic contributions of local lattice distortion, enhanced Pt-W bonding, increased energy barriers for stacking fault formation, and elevated Peierls stress. And provide atomistic insight into W-induced strengthening in Pt and contribute to a fundamental theoretical understanding of strengthening and thermal stabilization in Pt-W alloys.