  A dimer of bound atoms cannot melt, only dissociate. Bulk metals show a well
defined first order transition between their solid and liquid phases. The
appearance of the melting transition is explored for increasing clusters sizes
via the signatures in the specific heat and the root mean square of the bond
lengths $\delta_{\rm B}$ (Berry parameter) by means of Monte-Carlo simulations
of Al clusters modelled by Gupta potentials. Clear signatures of a melting
transition appear for $N\sim 6$ atoms. Closed-shell effects are shown for
clusters with up to 56 atoms. The melting transition is compared in detail with
the dissociation transition, which induces a second and possibly much larger
local maximum in the specific heat at higher temperatures. Larger clusters are
shown to fragment into dimers and trimers, which in turn dissociate at higher
temperatures.
