INVERSE MELTING IN A SYSTEM WITH POSITIVE HEATS OF FORMATION

Supersaturated body-centered-cubic Fe-W solid solutions with positive heats of formation were prepared by cosputtering and mechanical alloyi ng over a wide concentration range. Upon annealing, these solid soluti ons were observed to undergo amorphization in the range of 20-37 at. % W. For Fe70W30 and Fe67W33 the transformation was polymorphous, indic ating an inverse melting behavior. A thermodynamic analysis of the Fe- W system, which was carried out using the calculation-of-phase-diagram s method, supported that inverse melting is energetically possible in the Fe-W system. The results demonstrate that inverse melting can also occur in systems with positive heats of amorphous phase formation. [S 0163-1829(97)51042-3].