Even being relatively costly, copper and copper-based
alloys are indispensable where high electrical and/or
thermal conductivity are required of a constructional alloy.
In modern engineering applications high conductivity
should often be combined with high strength, fatigue endurance
and other mechanical properties not intrinsic for copper.
Energy, automobile, vehicle and aerospace industries,
nuclear engineering and thermal energetics specify enhanced
demands to the combination of mechanical and physical
properties of copper-based alloys.
For example, resistance welding electrodes, which are
widely used in the industry, must possess high electrical
conductivity and withstand a cyclic loading at elevated
temperatures. Application of high-strength thermal conductors,
cables, parts of electric power plants, electric motors,
generators, various heat exchangers is very topical.
A material for coils of high-field constant magnets should
combine high conductivity to minimize the heat production with
the mechanical strength sufficient to withstand the Lorentz
Precipitation hardening and cold rolling are conventionally
used for hardening of Cu-based alloys. At the same time a vast
bulk of research results shows that refining of crystalline
structure of precipitation hardened copper alloys provides
best mechanical characteristics with high thermal stability,
preserving sufficiently high electrical conductivity. Severe
plastic deformation techniques, which allow obtaining high
strength characteristics for copper alloys, were developed in
the Institute of Physics of Advanced Materials. For the sake
of comparison, the data on physical and mechanical
characteristics of copper alloys after conventional
treatment techniques and after various combinations of
severe plastic deformation techniques are presented.
In UFG materials the main structural strengthening feature
is a high density of grain boundaries, these materials
demonstrate behavior quite different from conventional
cold-worked materials, strengthened mostly by dislocation
pile-ups. Better mechanical and thermal stability, higher
ductility and an ability to absorb large doses of neutron
radiation without considerable recovery and other adverse
effects are among the differences. The last property is of
particular interest for aerospace industry and nuclear
engineering and, first of all, for thermal energetics.
Now, when reliable SPD technologies for production of bulk
UFG metals are available, material performance for many
important applications may be considerably improved.
Some physical and mechanical properties of copper-based
alloys after various treatments of semi-products