Paper Title
Study Of Globularization In Ti-6al-4v Alloy During Non-Isothermal Multiple Forging And Annealing

Abstract
In present work the mechanisms of globularization i.e. breaking of initial α colony structure during multiple forging and post deformation annealing process at different temperatures (700C to 950C) has been analyzed. A workpiece (94 mm x 120 mm) of Ti-6Al-4V alloy with starting initial α-colony structure was heated at 850C and subjected to successive upsetting and drawing operations without intermediate heating, followed by water quenching. The deformed Ti-6Al-4V alloy consists of heterogeneous microstructure with kinked, sheared and unreformed α lamellae. Microstructure evolution mechanism during successive upsetting or drawing operations is proposed here. Globularization of thin inter-lamellar β phase was observed after post deformation annealing at 800C. The process of static globularization was found to be accelerated by increase in annealing temperature above 900C via mechanisms like boundary splitting, edge spheroidization and cylinderization. Index Terms- Annealing, Globularization, Non-isothermal multiple forging, Ti-6Al-4V alloy