<p>The effect of re-crystallization annealing followed by standard mill annealing on the tensile properties and fracture toughness of a titanium alloy Ti6Al4V alloy hemispherical closed die forged domes has been studied. Tensile and fracture toughness (K_Ic) samples were cut from the two hemispherical domes having a nominal Ø400mm and 20&#xa0;mm thickness in two different heat-treated conditions: Forged + standard Mill annealed (MA) and Forged + re-crystallization annealed + standard Mill annealed (RMA). The obtained results met the minimum specified tensile properties and fracture toughness in both MA and RMA conditions. Introducing re-crystallization annealing before standard Mill annealing has resulted in significant improvement in fracture toughness compared to standard mill annealed condition which can be attributed to the finer α grain size and thereby higher volume fraction of grain boundaries per unit volume, which act as a more tortuous path for crack propagation in RMA condition as compared to that in MA condition.</p>