  Non-uniform temperature fields are analyzed, which arise in the problems of
formation of the steady shock wave at impact and ramp loading of metals, exit
of the steady shock wave to the free surface, and the shock wave passing
through the interface between two different materials. Theoretical analysis and
computations show that high-entropy (with the temperature increase) and
low-entropy (with the temperature decrease) layers arise near the interfaces in
the above problems of shock and ramp loading. The impact produces the
high-entropy layer; while the ramp loading can result in the both high- and
low-entropy layers. At the shock wave passing through the interface, the
high-entropy layer is formed in the lower-impedance material and the
low-entropy -- in the higher-impedance one. The formation of high-entropy layer
at impact is supported by molecular-dynamics simulations in addition to
continuum modeling. The high- and low-entropy layers should be taken into
account in simulations of shock-wave processes in thin targets or in other
cases where surface effects are important.
