Hot deformation and dynamic recrystallization behavior of Cu-3Ti-3Ni-0.5Si alloy

Abstract

Hot deformation characteristics and dynamic recrystallization of Cu-3Ti-3Ni-0.5Si alloy were studied systematically in the range of 700–850 °C and at the strain rate of 0.01–10 s−1. The results show that the peak stress increases with decrease of temperature or increase of strain rate. The stress values of true strain are used for constructing constitutive equations and the constitutive equation model can well predict the flow stress of the Cu-3Ti-3Ni-0.5Si alloy. The processing map based on the dynamic materials model is composed of a power dissipation map and an instability map and the processing map show that an appropriate hot working process is in the range of 750–800 °C and at the strain rate of 0.1 s−1. After hot compressive deformation at 850 °C with different strain rates, the volume fraction of dynamic recrystallization decreases with increasing strain rate. The dislocation tangle and dislocation pile-up generate close to the precipitate. The recrystallized nuclei appeared on the surface of the coarse precipitates and a small number of recrystallized nuclei formed at the trigeminal boundary can effectively promote the growth of the dynamic recrystallized nuclei. The precipitation of Ni3Ti phase promotes the nucleation of dynamic recrystallization, and is beneficial for the formation of stability deformation domains. The precipitation of Ni2Si phase inhibits the occurrence of dynamic recrystallization, giving rise to the formation of instability deformation domains.