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

Molecular dynamic simulation of low-energy atomic recoils has been carried out for alpha-Fe (bcc) and alpha-Ti (hcp). Many-body interatomic potentials have been employed with modifications suitable for short-range interactions. This is the first systematic study of atomic displacement events in the bcc and hcp structures using such potentials. The displacement threshold energy, E(d), has been investigated in detail for Ti, and the strong dependence of E(d) on orientation has been interpreted in terms of the number of atoms temporarily displaced into interstitial positions during a threshold event. E(d) has also been obtained for Fe and is discussed in a similar manner. In addition, displacement cascades of up to 500 eV have been simulated for this metal, and the efficiency factor for defect production is found to be strongly dependent on recoil energy in this energy regime.