Publication

Abstract : The current study investigates the effect of annealing treatment on microstructure, mechanical, and electrochemical behavior of α+β dual-phase Ti6Al4V alloy. The as-received wrought Ti6Al4V alloy showed bimodal microstructure consisting of irregular-shaped primary αp and lamellar α/β. With increasing annealing temperature, irregular αp and lamellar α/β phase transformed into equiaxed and finally fully lamellar (α+β) structure accompanied by variation in β fraction, grain boundary density, and texture. The formation of equiaxed α phase takes place through splitting at low angle grain boundary. The alloy annealed at 850 °C exhibited the highest tensile strength attributed to α/α grain boundary strengthening. As-received sample showed the lowest current density during the potentiodynamic polarization indicating superior corrosion resistance as high grain boundary density play decisive role over the adverse effect of α-β galvanic coupling. XPS analysis revealed that high grain boundary density has pivotal role in promoting the formation of stable TiO₂ passive film characterized by higher Ti⁴⁺ fraction and reduced chloride adsorption.