Microstructure of Ti-Ag immiscible alloys with liquid phase separation

Ti-Ag alloy is characterized by a flat liquidus line in the binary phase diagram. The microstructure of binary Ti-Ag alloys was investigated in terms of liquid phase separation. In the Ti-rich Ti66.67Ag33.33 alloy, the conventionally cast ingot showed a dendritic structure that included Ti-Ag-based intermetallic compounds; on the other hand, the rapidly solidified melt-spun ribbon showed a particulate microstructure comprising Ag-rich globules and a Ti-rich matrix phase. The formation of emulsion-like structures in the rapidly solidified specimens can be explained in terms of liquid phase separation. In the Ag-rich Ti33.33Ag66.67 alloy, macroscopic phase-separated ingots were obtained via liquid phase separation. The metastable liquid miscibility gap in Ti-Ag alloy system was discussed based on thermodynamics. (C) 2017 Elsevier B.V. All rights reserved.