Abstract :
Methods of severe plastic deformation of
ductile metals and alloys offer the possibility of
processing engineering materials to very high strength
with good ductility. After typical amounts of processing
strain, a submicrocrystalline material is obtained,
with boundaries of rather low misorientation angles
and grains containing a high density of dislocations. In
the present study, an Al–Mg–Si alloy was severely
plastically deformed by equal channel angular pressing
(ECAP) to produce such a material. The material was
subsequently annealed for dislocation recovery and
grain growth. The strength of materials in various
deformed and annealed states is examined and the
respective contributions of loosely-arranged dislocations,
many grain boundaries, as well as dispersed
particles are deduced. It is shown that dislocation
strengthening is significant in as-deformed, as well as
lightly annealed materials, with grain boundary
strengthening providing the major contribution thereafter.
