Thermomigration produced by collision cascades in solid solutions - art. no. 174105

Using the molecular dynamics of a model system, we determine the role of th ermomigration, one of the thermodynamic forces that may affect the mass tra nsport under the extreme conditions of time, temperature. and length scales characteristics of a heat spike following a collision cascade. By studying heat spikes in liquid alloys, we are able to isolate the Soret effect and measure the magnitude of the heat of transport Q*. We find that this effect can give rise to an increase or a decrease of solute content in the core o f a cascade. We show the particular case of the Au-Ni system (complete solu bility in the high-temperature solid phase and above), in which Ni as a sol ute in Au has a tendency to move toward the hut core of the spike. The oppo site is true for Au as a solute in Ni. This effect appears in a system whos e initial condition before irradiation is the equilibrium thermodynamic pha se predicted by the phase diagram. and therefore no solute motion is expect ed.