Strength and thermal stability of nanocrystalline gold alloys

By additions of Cu and Sn elements, we have synthesized nanocrystalline Au–Cu and Au–Cu–Sn materials with a minimum grain size down to ∼3 nm. Tensile measurements of these nanocrystalline materials indicate that the Hall–Petch scaling law is maintained to the smallest length scale. Though Cu and Sn solid solutions are observed to have little effect on the strength of nanocrystalline Au, they substantially enhance the thermal stability of these alloys. Abnormal grain growth no longer becomes the characteristic feature of alloyed nanocrystalline Au.