Interface Stability in Driven Compounds

Abstract

To model the behaviour of an ordered alloy under irradiation, we propose a mean-field approximation of the B2-A2 order-disorder transition on a B.C.C. lattice with two atomic exchange mechanisms acting in parallel: thermally activated and forced jumps. By integration of deterministic evolution equations, we show that irradiation can induce the stabilization of a two-phase alloy, while the classical equilibrium phase diagram only displays single phase fields (the B2-A2 transition is second order). The steady-state diagram is computed: in the two-phase region, the lever rule is obeyed and surface tension effects are identified; a new mechanism for precipitate redistribution under irradiation and shearing is discovered.