Characterization of Hot Workability of 5 vol.%TiBw/TA15 Composites of Meshed Structures Based on Hot Processing Maps and Microstructure Evolution

To clarify the hot deformation process characteristics of 5 vol.%TiBw/TA15 composites with three-dimensional (3D) meshed structures, isothermal compression experiments are performed at the temperature of 1173-1373 K with strain rates of 0.001-1 s(-1). Two criteria (Prasad and Murty) are employed to study the hot workability of the TiBw/TA15 composites. It is found that typical deformation instability defects (flow localization) are observed in the instability domains in the processing maps. The effects of strain rates and deformation temperatures on the microstructure evolution of the composites are also investigated. The flow stress curve is a manifestation of the deformation behavior of the material, which could reflect a part of the deformation behavior. To better understand the relationship between flow stress and hot deformation parameters, the constitutive equations of composites in the different phase regions (alpha + beta region and beta region) are established by combining the deformation temperature, strain rates and true strain. The calculation results show that the hot deformation activation energy is 563.487 kJ mol(-1) and 255.084 kJ mol(-1) in the alpha + beta phase region and beta single-phase region, respectively. The experimental results could facilitate the understanding of the hot deformation behavior of 5 vol.%TiBw/TA15 composites.