MOLECULAR-DYNAMICS CALCULATION OF THE ZR(NI) ENTHALPY OF MIXING

The Zr-terminal portion of the Ni-Zr phase diagram was studied by mean s of molecular dynamics simulations. The internal energy and the entha lpy of mixing at 300 K of the alpha- and beta-Zr(Ni) solid solutions a nd of the Zr-Ni amorphous phase were calculated for Ni concentrations less than or equal to 10 at. %. The values of the enthalpy of mixing o btained are positive for the terminal solid solutions, and negative fo r the amorphous phase. This behavior is attributed to the differences in strain energy generated in the Zr lattice or in the amorphous phase by Ni atoms. Implications of these results relevant to the problem of amorphization in metallic systems by solid-state reactions are discus sed. (C) 1996 American Institute of Physics.