A dramatic increase in the strength of a nanoporous Pt–Ni alloy induced by annealing

The microstructure and mechanical strength of a nanoporous Pt–Ni alloy were characterized before and after 300 °C annealing for 1 h. After annealing microhardness increased significantly from 2.1 to 3.8 GPa, while the relative density, ligament morphology and size remained unchanged. The annealing-induced strength increase is believed to be due to microstructure relaxation and grain growth. This study suggests that the mechanical properties of nanoporous metals depend not only on the relative density, ligament size and morphology, but also on the structure inside ligaments.