The influence of pre-annealing on thermal stability of the amorphousZr_(70)Cu_(20)Ni_(10) alloy was reported by employing the differential scanning calorimetry (DSC)and high-resolution transmission electron microscopy (HRTEM) techniques. It has been observed thatthe supercooled liquid region decreases with increasing the annealing time under isothermalconditions, indicating that the thermal stability of the amorphous Zr_(70)Cu_(20)Ni_(10) alloydecreases gradually. HRTEM observations reveal that there exist some ordered atomic clusters in theamorphous matrix at the relaxation stage. These ordered atomic clusters can be regarded asprecursors for the precipitation of the crystalline phases in the subsequent crystal-lizationprocess. The reasons resulting in the decrease in thermal stability of the amorphousZr_(70)Cu_(20)Ni_(10) alloy with annealing time are discussed through the Gaussian decomposition forthe radial distribution function of the amorphous Zr_(70)Cu_(20)Ni_(10) alloy.
The liquid structure of Fe-4.30C and Fe-4.30C-0.21Ce alloys was studied by high temperature X-ray diffractometer. The results show that for Fe-C alloy the nearest neighbor distance of the eutectic alloy is 0.259-0.260 nm at the temperature range of 1200-1400℃, 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 temperature 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 can meet 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 increases with the decreasing temperature.
