Microstructure evolution of near-α titanium alloys during thermomechanical processing

In this work, near-alpha Ti-1100 alloys with TiC (1 vol.%) ceramic particles reinforcement were fabricated. After casting, ingots breakdown was performed at 1150 degrees C. The volume fraction of the primary a-phase in the microstructure as a function of heated temperature, and the beta(t) temperature of this material, were examined by metallographic method. The ingots after break-down were forged using various thermomechanical processing parameters. According to whether the deformation was performed in the beta-phase field, the alpha + beta-phase field, or the upper a-phase field, four types of hot deformation are recognized: deformation in the P-phase field; deformation started in the P-phase field and finished in a + P-phase field; deformation in alpha + beta-phase field; deformation in the upper a-phase field. The characteristics of the microstructural evolution are different for the four types of deformation process. The final microstructures of this alloy after thermomechanical processing are depended on two factors. One is the thermomechanical processing process, and the other is the cooling process after hot deformation. The result will deepen the understanding of the microstructural characteristics of near-a titanium alloy during thermomechanical processing and optimize the microstructural control. (c) 2005 Elsevier B.V. All rights reserved.