Influencia de la adición de estaño en el proceso de precipitación en una aleación de Cu-Ni-Zn

The influence of 1.1 wt% tin additions on the precipitation hardening of Cu-11 wt% Ni-20 wt% Zn alloy was studied by Differential Scanning Calorimetry (DSC), microhardeness measurements and High Resolution Transmission Electron Microscopy (HRTEM). The calorimetric curves, in the range of temperatures analyzed, show the presence of two exothermic reactions in the ternary alloy, associated to the short-range-order development assisted by migration of excess vacancies. On the other hand, one exothermic and one endothermic reaction are observed in the quaternary alloy, associated to the formation and dissolution of Cu 2 NiZn precipitates, respectively. It has been show that an addition of 1.1% tin plays an important role in the formation of Cu 2 NiZn precipitates, responsible for the precipitation hardening of the ternary alloy.