Microstructure and Fracture Characteristic of Aluminium — Zinc — Titanium Alloys

The microstructure is one of the significant factors that influence the mechanical properties of the material. The microstructural characteristics of heat treated and untreated Al-Zn-Ti alloys were stuided with optical microscopy, TEM, and SEM fractography. The results indicate that a proper treatment causes a significant improvement in the toughness of the material and decrease the tendency of the brittle fracture at low temperatures. An increase in both tensile strength and yield stress is also recognised. These findings are mainly related to the well-distributed precipitates, the elimination of precipitate free zone (PFZ) and the elimination of discontinuous intergranular precipitates.