[en] Full text: Copper-based alloys are widely used in many fields because of the combination of high thermal and electrical conductivities with good mechanical properties. In particular, Cu-based alloys with high performance are required in field of electronic materials (such as substrate and lead frame in printed boards, interconnection and so on) because the electronic packageing has a tendency to miniaturization [1]. In this work the effect of heat treatment on the characteristics of the Cu-14.99at.%Al-10.53at.%Mn-1.61at.%Gd alloy was studied using microhardness measurements with temperature (MM), differential scanning calorimetry (DSC), differential thermal analysis (DTA), optical microscopy (OM) and X-ray diffractometry (XRD). In annealed samples the α, T₃ -Cu₃Al₂Mn and Cu₆ Gd phases were identified at room temperature and the DSC curves obtained from room temperature up to 870 K, after slow cooling at 1 K/min, showed all phase transitions expected for Cu-Al-Mn alloys. For quenched samples the α and b phases were identified at low temperature and the DSC curves obtained from room temperature up to 870 K, after fast cooling from 1123 K in iced water, showed the presence of the bainite precipitation at 570 K. The microhardness curve with temperature obtained for quenched sample showed that the bainite precipitation in the Cu-14.99at.%Al-10.53at.%Mn-1.61at.%Gd alloy promotes an increase in microhardness, as expected for Cu-Al-Mn alloys. In conclusion, the results indicated that the behavior of this alloy at high temperature is similar to that expected for Cu-Gd alloys, but at low temperature the phase transitions detected are related to those observed in Cu-Al-Mn alloys, independently of the heat treatment. Reference [1] H. N. Soliman, N. Habib, Effect of ageing treatment on hardness of Cu-12.5 wt% Al shape memory alloy. Indian J. Phys. DOI 10.1007/s12648-014-0480-z .(author)