THE EFFECT OF ISOTHERMAL MULTIDIRECTIONAL FORGING ON THE MICROSTRUCTURE AND PROPERTIES OF Cu–40%Zn–2%Mn ALLOY

The deformation behavior and changes in the microstructure of manganese brass Cu–40%Zn–2%Mn (wt%) during multidirectional isothermal forging (MDF) at temperatures of 400°C and 500°C, which is ~ 50°C lower and higher than the temperature of the β–β' transition, were studied. It has been shown that MDF at both temperatures promotes the formation of a homogeneous and fine-grained structure with an average grain size of α- and β'-phases of ~ 5 and ~ 12 microns, respectively, increasing the hardness by 2.5 times from 130 HV in the initial state to ~ 310 HV after the total true deformation Σε = 7.2. An increase in the true strain to Σε = 14.4 did not have an additional strengthening effect. In the case of MDF at 400°C, an increase in the true deformation was accompanied by a slight grinding of the grains of the α and β' phases to 3.6 and 9.2 microns, respectively, and in the case of deformation at 500°C, it led to an increase in their sizes to 7.1 and 17.5 microns, respectively.