Specific Features and Regularities of Melting and Crystallization Processes in Binary Metallic Alloys

Resumo

The melting and crystallization processes in some binary alloys based on the Ag–Cu model system have been studied by high-resolution differential scanning calorimetry. The crystallization and melting is found to be accompanied by heat flow jumps as the liquidus line is achieved or the melting process is completed. During crystallization, these phenomena are assumed to be related to the formation in a liquid of a great number of local microvolumes (concentration fluctuations) enriched in the component leading the crystallization. Their appearance precedes the process of spontaneous formation and growth of many crystals of a new phase. It is established that our concepts on the crystallization and melting processes in binary metallic alloys should be complemented.