Bulk nanostructured composite materials can be obtained by partial devitrif
ication of slowly cooled bulk glass-forming multicomponent metallic glasses
or by blending a glassy matrix alloy with insoluble second-phase particles
by solid state processing. Their properties are discussed with respect to
the effect of the second phases on the thermal stability and on the mechani
cal properties at room temperature as well as at temperatures around the gl
ass-transition temperature, T-g. Microhardness measurements at room tempera
tures reveal a substantial increase in the hardness of the composites becau
se of the uniform distribution of nanoscale particles in the glossy matrix.
Also, there is a significant increase in yield strength with increasing vo
lume fraction of particles. At elevated temperatures around T-g volume frac
tions of up to 40 vol-% of nanoscaled particles yield no significant change
in strength as compared with the particle-free material, but the deformati
on behavior of the composites is mainly controlled by the Newtonian viscous
flow of the glassy matrix phase. This easy-flow behavior opens a promising
route for shaping complex parts of bulk nanostructured composites derived
from metallic glasses at moderate temperatures and high strain rates.