Influence of deformation parameters and network structure to the microstructure evolution and flow stress of TiBw/Ti64 composite

Abstract

Titanium matrix composites (TMCs) play important roles in the weight reduction of the modern aero-space industry due to the excellent combination of strength and ductility. Especially, titanium matrix composites with network architecture have drawn much attention in recent years. To better understand the influence of deformation temperature, strain rate and the network size over the microstructure evolution and the flow stress of network structured TMCs, 8 vol.% TiBw/Ti64 composites with network sized 65 μm, 110 μm and 150 μm were prepared for thermal compression test. The results showed that the decrease in deformation temperature and the increase of the strain rate will prompt the dynamic recrystallization process, thereby producing refined equiaxed α grains. Multiple changes were observed accompanying the decrease of network size, including the refinement of the deformation microstructure, the drop of compressive flow stress, as well as the decrease of the texture intensity. It was also found that, the texture of specimens deformed in β region was inherited from the texture of body centered cubic (BCC) β phase through β→α transformation, abiding by Burgers relationship. Moreover, preference in variants selection during β→α transformation was observed, which is an important factor for the formation of texture in β phase deformation.