COMPUTER-SIMULATION OF LOW-ENERGY DISPLACEMENT EVENTS IN PURE BCC ANDHCP METALS

Molecular dynamic simulation of low-energy atomic recoils has been car ried out for alpha-Fe (bcc) and alpha-Ti (hcp). Many-body interatomic potentials have been employed with modifications suitable for short-ra nge interactions. This is the first systematic study of atomic displac ement events in the bcc and hcp structures using such potentials. The displacement threshold energy, E(d), has been investigated in detail f or Ti, and the strong dependence of E(d) on orientation has been inter preted in terms of the number of atoms temporarily displaced into inte rstitial positions during a threshold event. E(d) has also been obtain ed for Fe and is discussed in a similar manner. In addition, displacem ent cascades of up to 500 eV have been simulated for this metal, and t he efficiency factor for defect production is found to be strongly dep endent on recoil energy in this energy regime.