AMORPHOUS SYSTEMS AND AMORPHIZATION

Abstract

Since ion irradiation can lead to high densities of displaced atoms in solids, one is led to the conjecture that it may possibly amorphize an initially crystalline lattice. Under what conditions can this occur? What relation does ion-induced amorphization bear to the near-equilibrium thermodynamic conditions for obtaining those specific metastable solid solutions that qualify as “glasses”? This chapter approaches the second question first, deliberately putting ion irradiation effects in the perspective of materials science, rather than the reverse. In that sense, it is rather complementary to the presentation given in Chapter 10 (Ossi). I first recall some background information and references on the main features of the amorphous state. I then discuss amorphization dynamics – with and without irradiation – emphasizing those properties, which are specifically obtained under irradiation. The following aspects have guided my presentation.