Effect of Si and Ti on dynamic recrystallization of high-performance Cu-15Ni-8Sn alloy during hot deformation
(1. Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials, South China University of Technology, Guangzhou 510640, China;
2. School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China)
2. School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China)
Abstract: Effect of Si and Ti on dynamic recrystallization (DRX) of Cu-15Ni-8Sn alloy was studied using hot compression tests over deformation temperature range of 750-950 °C and strain rate range of 0.001-10 s？1. The results show that the dynamic recrystallization behavior during hot deformation is significantly affected by the trace elements of Si and Ti. The addition of Si and Ti promotes the formation of Ni16Si7Ti6 particles during hot deformation, which promotes the nucleation of dynamic recrystallization by accelerating the transition from low-angle boundaries (LABs) to high-angle boundaries (HABs). Ni16Si7Ti6 particles further inhibit the growth of recrystallized grains through the pinning effect. Based on the dynamic recrystallization behavior, a processing map of the alloy is built up to obtain the optimal processing parameters. Guided by the processing map, a hot-extruded Cu-15Ni-8Sn alloy with a fine-grained microstructure is obtained, which shows excellent elongation of 30% and ultimate tensile strength of 910 MPa.
Key words: Cu-15Ni-8Sn alloy; discontinuous dynamic recrystallization; hot compression; hot extrusion; mechanical properties