  The theory and experiments concerned with the electron-ion thermal relaxation
and melting of overheated crystal lattice constitute the subject of this paper.
The physical model includes two-temperature equation of state, many-body
interatomic potential, the electron-ion energy exchange, electron thermal
conductivity, and optical properties of solid, liquid, and two phase
solid-liquid mixture. Two-temperature hydrodynamics and molecular dynamics
codes are used. An experimental setup with pump-probe technique is used to
follow evolution of an irradiated target with a short time step 100 fs between
the probe femtosecond laser pulses. Accuracy of measurements of reflection
coefficient and phase of reflected probe light are ~1% and $\sim 1\un{nm}$,
respectively. It is found that,
  {\it firstly}, the electron-electron collisions make a minor contribution to
a light absorbtion in solid Al at moderate intensities;
  {\it secondly}, the phase shift of a reflected probe results from heating of
ion subsystem and kinetics of melting of Al crystal during $0<t<4\un{ps},$
where $t$ is time delay between the pump and probe pulses measured from the
maximum of the pump;
  {\it thirdly} the optical response of Au to a pump shows a marked contrast to
that of Al on account of excitation of \textit{d}-electrons
