Microstructure evolution during forging deformation of (TiB+TiC+Y2O3)/α-Ti composite: DRX and globularization behavior

Abstract

In this work, the β and (α+β) forging deformation were conducted on (TiB + TiC + Y2O3)/α-Ti composite to investigate the effect of reinforcement on dynamic recrystallization and globularization behavior. During β deformation, the reinforcements not only accelerated discontinuous dynamic recrystallization by particle stimulated nucleation mechanism, but also promoted the heterogeneous nucleation of α phase thus conducted the {0001}α pole figure of composite more widely distributed. However, during (α+β) deformation, the microstructure was characteristic of kinked α colonies morphology. Moreover, compared to matrix, the (TiB + TiC + Y2O3)/α-Ti composite depicted a more homogeneous microstructure and larger crystallography rotation both along or transverse to the α lamellar. The distribution of Schmid factor value indicated that the deformation behavior of matrix showed varies with the α colony while it was more homogeneous in composite. Reinforced with (TiB + TiC + Y2O3) reinforcements, on the one hand, the random SF value of composite conducted the incompatibility slip between adjacent α lamellar thus at last leaded the formation of HABs in inter-lamellar; on the other hand, the reinforcement itself could obstruct dislocation that accelerated the dynamic globularization behavior. Therefore, the (TiB + TiC + Y2O3)/α-Ti composite had a great advantage in optimizing microstructure especially globularization that made the composite of great application prospect.