It has been found that rare earth elements and Si are effective in
strengthening fine gold [11,14,15]. In the present work, we investigate
the effect of simultaneous addition of Ce and Si on mechanical
property of gold. We show that hardness of gold can be
nearly doubled by simultaneous addition of small amount (less
than 0.1% by weight) of rare earth element Ce and Si, and tripled by
subsequent cold rolling. We further investigate the microstructure
origin leading to the greatly enhanced hardness.