This study investigates the corrosion behavior and microstructural changes of Cu/Al/Cu three-layer tubes after post-weld heat treatment in the explosive welding process. The heat treatment was performed by varying the temperature. Polarization tests and electrochemical impedance spectroscopy were employed to examine the corrosion behavior of the weld zone. Additionally, metallographic examination using optical microscopy (OM) and scanning electron microscopy (SEM) was conducted to study the microstructure. The electrochemical impedance spectroscopy results showed that the value of “n” in the heat-treated sample at 300°C and explosion load of 2.8 had a lower value compared to the heat-treated sample at 300°C and explosion load of 3.2, indicating higher corrosion current in the heat-treated sample at 300°C and explosion load of 2.8, leading to a decrease in charge transfer resistance. By comparing the heat-treated samples at 300°C and explosion load of 2.8 with the ones heat-treated at 400°C and explosion load of 2.8, with variable annealing temperature and constant annealing time, the sample heat-treated at 400°C exhibited a higher value of n (0.77), while the heat-treated sample at 300°C and explosion load of 2.8 had a lower value of n (0.69), attributed to the increase in annealing temperature and the decrease in stored energy in the joint. تفاصيل المقالة