This thesis focuses on determining the optimal process annealing heat treatment for the aluminum alloy EN AW-3057, which belongs to the 3XXX series and contains manganese as the main alloying element. Aluminum, known for its light weight, corrosion resistance, and good electrical conductivity, is crucial in industries such as aerospace, automotive, and packaging. The mechanical properties of aluminum alloys can be significantly influenced by the alloy composition and the applied heat treatment processes, where process annealing plays an important role in controlling the microstructure and thus the mechanical properties of wrought alloys.
In this research, we analyzed the impact of different temperatures and durations of process annealing on the mechanical properties of the EN AW-3057 alloy, such as tensile strength, yield strength, and elongation. The goal was to determine whether all the parameters of inter-annealing ensure mechanical properties that meet the standard requirements for the EN AW-3057 alloy. Using differential scanning calorimetry, we then investigated whether the enthalpy of melting and solidification changes compared to the current industrial process annealing, which is conducted at 350 °C for 3 h, changes when the temperature and time of the process annealing change.
The analysis results indicate that a properly selected process annealing can significantly improve the mechanical properties of the aluminum alloy EN AW-3057. We found that almost all the heat treatments we performed provided mechanical properties consistent with the standard requirements for our alloy. Only the heat treatment conducted at 250 °C for 1 h did not meet this standard. We also determined that the process annealing at 300 °C for 2 h is the most optimal, as the values of the mechanical properties are neither at the upper nor the lower limit of the permissible range required by the standard. Additionally, we discovered that a properly chosen process annealing reduces the energy requirements of the procedure. The enthalpies of melting and solidification decrease after the heat treatment in the case of the current process annealing regime (350 °C – 3 h). In the case of optimized heat treatment (300 °C – 2 h), compared to the hard state of the material (H18), the enthalpies of melting and solidification slightly increase.
Such optimization is important for the industry as it contributes to sustainable production and efficient use of aluminum alloys, where low weight, high strength, and energy efficiency are of crucial importance.
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