The effect of Sn-rich phases on dynamic recrystallization behavior of Cu-9Ni-6Sn-(0.05 Nb) alloys

In this work, the number and size of Sn-rich phases were found to be different in Cu-9Ni-6Sn alloys with the different Nb addition. A low fraction of Sn-rich phases, located between secondary dendrite arms, was achieved in the Cu-9Ni-6Sn-0.05 Nb alloy. The subsequent hot deformation behavior of Cu-9Ni-6Sn-(0.05 Nb) alloys was investigated at a temperature range of 750 ℃ ∼ 850 ℃ and a strain rate of 0.01 s−1. The results revealed that the different distribution of Sn-rich phases changed the dynamic softening mechanism in two alloys during hot compression. Due to the distribution of a large number of Sn-rich phases in the grain interior, the dynamic softening mechanism observed during hot compression in Cu-9Ni-6Sn alloy was particle stimulated nucleation (PSN) and continuous dynamic recrystallization (CDRX). In contrast, the major dynamic softening mechanism in Cu-9Ni-6Sn-0.05 Nb alloy were discontinuous dynamic recrystallization (DDRX) and CDRX due to a different distribution of Sn-rich phases. This study provides a fundamental guide for further research on Cu-Ni-Sn alloy fabrication based on the results of dynamic softening mechanisms obtained from the hot compression experiment.