Devitrification of Ni-based glassy alloys containing noble metals in relation with the supercooled liquid region

Abstract The formation of the supercooled liquid region and devitrification behavior of Ni-based glassy alloys were studied by using X-ray diffraction, transmission electron microscopy, differential scanning calorimetry and isothermal calorimetry. oC68 Ni 10 Zr 7 -type phase is primarily formed in the studied alloys in the initial stage of the devitrification process by nucleation and three-dimensional diffusion controlled growth. The replacement of Cu by Ni in Cu 55 Zr 30 Ti 10 Pd 5 glassy alloy induces precipitation of oC68 Ni 10 Zr 7 phase directly from the glassy phase. The reasons for such a behavior are discussed taking into account mixing enthalpy in a liquid state and the interval of the supercooled liquid region.