Martensite decomposition in Cu–Al–Mn–Ag alloys

•Martensite decomposition in Cu–Al–Mn–Ag alloys is mainly influenced by Mn.•Interaction between Cu–Mn atomic pairs increases activation energy.•Cu diffusion is disturbed by the interaction between Cu–Mn atomic pairs. The influence of Mn and Ag additions on the isothermal kinetics of martensite decomposition in the Cu–9wt.%Al alloy was studied using X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXS) and microhardness changes measurements with temperature and time. The results indicated that the reaction is disturbed by the increase of Mn, an effect associated with the increase in the Al–Mn and Cu–Mn atomic pairs, which disturbs Cu diffusion and increases the activation energy for the martensite decomposition reaction.