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

• Published in: Journal of alloys and compounds Vol. 782; pp. 224 - 234
• Main Authors: Liu, Jia, Wang, Xianhui, Liu, Jituo, Liu, Yanfeng, Li, Hangyu, Wang, Chan
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25.04.2019; Elsevier BV
• Subjects: Constitutive equations; Constitutive relationships; Copper alloy; Copper base alloys; Deformation; Dislocations; Domains; Dynamic recrystallization; Dynamic stability; Hot working; Nucleation; Nuclei; Precipitates; Process mapping; Processing map; Recrystallized nucleus; Strain rate; True strain; Yield strength; Processing map; Dynamic recrystallization; Recrystallized nucleus; Constitutive equations; Copper alloy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.12.212

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. •The flow stress of the Cu-3Ti-3Ni-0.5Si alloy can be well predicted by the constitutive equation model.•The processing map illustrates that the appropriate hot working was at 750–800 °C and 0.1 s−1.•The volume fraction of dynamic recrystallization decreases with increasing strain rate at 850 °C.•The process of dynamic recrystallized nucleus is disclosed.•The correlation between dynamic recrystallized nucleus and precipitation is clarified.