Effect of Sn addition on high temperature softening resistance of Cu-3Ni-0.75Si-0.1Mg alloy and its mechanism

Abstract

Cu-3Ni-0.75Si-0.1Mg-xSn alloys with different Sn contents were prepared by medium frequency induction melting furnace, and the influence of Sn addition on high temperature softening resistance of the Cu-3Ni-0.75Si-0.1Mg alloy and its mechanism were studied. The results show that the addition of Sn elements can increase the peak hardness of the alloy, and with the increase of Sn content, the increment effect is more significant. The addition of 0.6% Sn can increase the softening temperature of the Cu-3Ni-0.75Si-0.1Mg alloy, which is mainly due to the fact that the addition of Sn element hinders the recovery and recrystallization of the alloy. The annealing softening mechanism of the Cu-3Ni-0.75Si-0.1Mg-xSn alloys in different annealing temperature ranges is different. When annealing at low temperature (450-500 ℃), the annealing softening is related to recovery, while annealing at medium temperature (500-600 ℃) is mainly affected by recovery and recrystallization. When annealing temperature is too high (>600 ℃), the annealing softening is mainly affected by the coarsening of second phase particles.