Phase Transformations in Vapor-Quenched Molybdenum and Molybdenum Gold Alloys.

Abstract : Thin films of Mo and of metastable single-phased Mo-Au alloys were prepared by vapor-quenching and subjected to a variety of aging treatments while their microstructural characteristics were studied by high resolution microscopy and through electric resistance measurements. When aged above 400C the alloys transformed by a complex process which involved competition among internal precipitation, surface precipitation and evaporation of the gold. The transformation was associated with resistance changes that followed second order kinetics, and activation energies that tended to increase as the transformation progressed. Depending upon the quality of the vacuum and the temperature of deposition amorphous, fcc and bcc modifications of molybdenum were produced. (Author)