Study on the effect of first step agetemperature on the mechanical properties and microstructure of Al-Cu-Mg alloy intwo steps aging process

In this research, the effect of first step age temperature during two steps aging process on the strength, ductility, hardness and microstructure of Al-Cu-Mg alloy has been investigated to obtain an optimum combination of strength and ductility. After solution treatment and quenching the samples in the water, they have artificially been aged for 2 hours in 175, 190, 205°C. Then the samples were naturally aged for 10, 50, 100 hours. To investigate the mechanical properties, all the samples were subjected to tensile test and microstructure analysis after each cycle. The data of one and two steps aging treatment and also the effect of first step temperature were compared. The results show that second step of natural aging by affecting the stability of precipitates and microstructure leads to change in tensile properties. With increasing the first step aging temperature, the impact of second step aging process decreases. Also two steps aging process with temperature of 190°C in first step and time of 50 hours in naturally aging results in and optimum combination of strength and ductility.