Anelastic collapse of small cavities in metals

The stability of a small cavity in a virtually infinite solid is studied in the context of anelasticity for two metals (Al and Cu). It is shown that the collapse occurs due to the dependence of the shear modulus on the relative volume change. It is shown that above a minimum external pressure P<inf>min</inf> the system cannot self-sustain, unless the internal pressure does exceed a critical value, compensating the collapsing effect. The different models of anelasticity adopted are shown to have a scarce influence on the main results. In particular, the value of P<inf>min</inf> turns out to range about the 10% of the bulk modulus at zero pressure, for both metals and almost independently from the anelastic model.