The influence of pre-annealing on thermal stability of the amorphous Zr70Cu20Ni10 alloy was reported by employing the differential scanning calorimetry (DSC) and high-resolution transmission electron microscopy (HRTEM) techniques. It has been observed that the supercooled liquid region decreases with increasing the annealing time under isothermal conditions, indicating that the thermal stability of the amorphous Zr70Cu20Ni10 alloy decreases gradually. HRTEM observations reveal that there exist some ordered atomic clusters in the amorphous matrix at the relaxation stage. These ordered atomic clusters can be regarded as precursors for the precipitation of the crystalline phases in the subsequent crystallization process. The reasons resulting in the decrease in thermal stability of the amorphous Zr70Cu20Ni10 alloy with annealing time are discussed through the Gaussian decomposition for the radial distribution function of the amorphous Zr70Cu20Nii0 alloy.
The liquid structure of Fe-4.30C and Fe-4.30C-0.21Ce alloys was studied by high temperature X-ray diffractometer. Theresults show that for Fe-C alloy the nearest neighbor distance of the eutectic alloy is 0.259-0.260 nm at the temperature range of1200-1400℃, which increases to 0.269-0.271 nm with the addition of 0.21% (mass fraction) Ce in the Fe-C alloy at the same tem-perature range. There is a pre-peak at Q = 15.5 nm-1 on the original intensity curve and structure factor S(Q) of the liquid Fe-4.30C-0.21Ce alloy, which was caused by the Ce atoms in the C-Ce clusters. Combined with the shared face, the tetragonal structure canmeet the requirement for the distance of Ce-Ce atoms. It also shows that the cluster size in the liquid Fe-4.30C-0.21Ce alloy in-creases with the decreasing temperature.
