2023 Volume 62 Issue 1 Pages 12-16
It is known that annealing 60/40 Cu–Zn alloy at relatively low temperatures causes bainitic transformation from the β1’ single–phase state to a plate–like α–phase, which affects the hardness of the brass. In this study, Ag, whose BOP value is comparable to that of Cu and Zn, was selected as an additive element, and the effects of the additive elements on the phase transformation were investigated using micro–Vickers hardness tests, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Comparing the alloys, the highest maximum hardness and the highest number density (N) of α–phase were observed in the 1.0Ag alloy. As quenched (as Q.) sample of 1.0Ag alloy showed the highest hardness value. The TEM observation results showed a stripe–like contrast caused by the 9R structure, which has been reported in this laboratory. A correlation existed between the aging effectivity (ΔHV) from as Q. to the maximum hardness and the density of stripe contrasts per unit volume in α phase.
