Microstructure evolution and mechanical properties response of a TZAV alloy during combined thermomechanical treatments

Abstruct crostructure evolution and mechanical properties response of a TZAV alloy during combined thermomechanical treatments containing hot rolling, cold rolling and subsequent annealing processes are investigated. Stress induced martensitic transformation presents after cold rolling and results in transformation from β to α″ phase. Few peaks of ω phase were observed in specimens annealed below 650 °C. The microstructure of cold rolled and low temperature annealed specimens are characterized by stretched β grains and fibrous structures. While annealed at 700 °C, the specimen has most of approximate granular α grains. The average aspect ratio of α grains increases as the annealing temperature increases. After annealing at 800 °C, the stretched β grains recrystallize into approximate equiaxed grains. Tensile testing results showed that the deformed specimens have lower strength than annealed specimens. Hardness results showed the similar trend with strength. Otherwise, the relationships between microstructural parameters and mechanical properties are also discussed in this work. Results show that the strength is greatly dependent on thickness of α grains and content of β phase but has little to do with shape parameters of α grians, conversely, the ductility is related to shape parameters but independent of thickness and content.