Deformation behavior and microstructure evolution mechanism of 5vol.% (TiB_w + TiC_p)/Ti composites during isothermal compression

Isothermal compression tests of as-cast 5vol.% (TiB_w + TiC_p)/Ti composites were conducted in the deformation temperature ranging from 900 to 1100 °C and strain rate ranging from 0.001 to 1.0 s⁻¹. The thermal deformation behavior and microstructure evolution mechanism of the material are studied to optimize the process parameters. Meanwhile, the flow stress-strain curves were measured. The activation energy decreases with increasing of compression temperature, which is related to the increase of β phase content with the increase of temperature. The constitutive equation was established to characterize the deformation behavior of 5vol.% (TiB_w + TiC_p)/Ti composites in hot compression. The softening mechanism is mainly dynamic recovery (DRV) and dynamic recrystallization (DRX) in different phase region. Transmission electron microscope (TEM) observation was used to study the effects of reinforcements on microstructural evolution. The results indicate that the reinforcement can prominently promote globularization of α lath in the α + β phase region. In the upper α + β phase region, the reinforcement promotes the formation of some subgrains in the matrix.