Precipitation behavior of Silicide in TiCp/Ti composites induced by hot deformation during β phase region

Abstract:

In this experiment, thermal physical simulation experiments were carried out on 5vol.%TiCp/near-α titanium matrix composites to investigate the precipitation behavior of silicides and the deformation mechanism of β phase during β phase region. After deformation, microstructure is mainly composed of lamellar α phase and broken TiCp at room temperature. The existence of (Ti,Zr)6Si3 silicides in the microstructure was confirmed by transmission electron microscopy (TEM)，with the grain size of 350-600nm. The numeber of silicides increases with the increasing temperature or decreasing strain rate. In addition, the parent β grains were reconstructed by α phase at room temperature. TiCp was distributed along the β grain boundary, which promoted the dynamic recrystallization of β phase by providing nucleation sites and hindering dislocation movement. The high-density dislocations induced and promoted the precipitation of silicides caused by accumulation of strain and TiCp during hot deformation.