Abstract:Microstructure refinement of a dual phase titanium alloy, Ti-3Al-4.5V-5Mo, by severe room temperature compression was investigated. Nanocrystalline grains were observed in the sample with 75% reduction, in which the grain sizes of α phase and β phase were approximately 50 and 100 nm. Conversely, the average thicknesses of α phase and β phase in as-received microstructure were measured to be 0.7 and 0.5 μm, respectively. TEM and XRD methods were used to analyze the microstructure and texture changes after severe deformation. Microstructure refinement was deduced to the complex interaction among slip dislocations in the α phase, the complex interaction among slip dislocations and martensites in the β phases. In addition, the interaction between the α phase and the β phase also contributed to the microstructure refinement.

Key words: dual phase titanium alloy; Ti-3Al-4.5V-5Mo alloy; severe plastic deformation; microstructure refinement; nanocrystalline grains; texture