Abstract
Non-isothermal and isothermal studies of the eutectoid decomposition in an A1–59at.%Zn alloy have been carried out using a resistometric technique. It is found that the decomposition occurs not only directly by a discontinuous process but that there also exists a continuous process. The rate of the discontinuous process depends very strongly on the degree of undercooling. At temperatures close to the critical temperature (550 K), the continuous process predominates at the beginning of the transformation. According to the presented model the products of continuous precipitation can be consumed by growing lamellae. The critical temperature and other parameters describing the kinetics of the process are estimated and are in agreement with both model considerations and other experimental data. Parts of the TTT (time-temperature-transformation) and CCT (continuous cooling transformation) diagrams have been determined.