## 5 Conclusions  
This study focused on evaluating the heat-treatment parameters of the 6061 aluminum alloy to enhance its mechanical properties. The effects of solutionizing and aging temperatures on the Ultimate Tensile Strength were investigated systematically using the Taguchi design of experiment (DOE) method. The following key findings and conclusions were drawn from the study:  
1. The mechanical testing results demonstrated a major influence of the solutionizing and aging parameters on the alloy's Ultimate Tensile Strength. The samples processed at a solutionizing temperature of 540 \({}^{\circ}\)C for 3 h, followed by aging at 170 \({}^{\circ}\)C for 18 h, exhibited the highest tensile strength (UTS = 293.7 MPa), while the samples processed at the lowest levels of these parameters showed the lowest tensile strength (UTS = 193.7 MPa). 2. The analysis of variance (ANOVA) revealed that aging temperature is the least influential factor affecting the Ultimate Tensile Strength. This factor has no statistically significant impact on the alloy's mechanical properties. However, it is essential for the final precipitation of the hardening phases and an important parameter in the heat-treatment process. 3. The microstructural analysis of the heat-treated samples confirmed the formation of equiaxed grains, strengthening precipitates, precipitate clusters, and \(\beta\) precipitates alongside Fe-Al-Si dispersoids. Energy-dispersive spectroscopy analysis also ratified the presence of elements precursors of the \(\beta\) phase (Al-Mg-Si) and dispersoid-forming elements (Al-Fe-Si). 4. X-ray diffraction analysis confirmed the presence of the \(\beta\) phase (Mg\({}_{2}\)Si) in the alloy, both in the as-received and heat-treated samples. The persistence of the \(\beta\) phase after the heat-treatment indicated its contribution to the improved mechanical properties. 5. Fracture analysis revealed a ductile fracture mechanism in the alloy. The examination of the fractured samples supported the findings of enhanced tensile properties resulting from the systematic evaluation of heat-treatment parameters from the Taguchi DOE and ANOVA assessment. The Taguchi DOE approach was successfully applied in this study to evaluate the heat-treatment parameters of the 6061-aluminum alloy by the analysis of variance. The results highlighted the significant impact of solutionizing and aging temperatures on the tensile strength, with the samples processed at higher levels of these parameters exhibiting superior mechanical properties. The microstructural and fracture analyses provided information about the mechanisms responsible for the improved properties, including the formation of strengthening precipitates and the persistence of the \(\beta\) phase. These findings contribute to the understanding and potential of enhancing the mechanical performance of the 6061-aluminum alloy in materials engineering applications and heat-treatment process optimization. **Author Contributions:** Conceptualization, I.G.-F. and E.E.G.-G.; methodology, R.J.P.-A., C.E.C.-G. and J.C.D.-G.; software, C.E.C.-G. and R.J.P.-A. ; validation, I.G.-F., R.J.P.-A., D.I.M.-D. and C.E.C.-G.; formal analysis, I.G.-F., H.M.H.-G., D.I.M.-D. and R.J.P.-A. ; investigation, I.G.-F., C.E.C.-G. and L.F.-G.; resources, I.G.-F., J.C.D.-G. and H.M.H.-G.; writing--original draft preparation, I.G.-F., R.J.P.-A. and L.F.-G.; writing--review and editing, E.E.G.-G.; visualization, J.C.D.-G., E.E.G.-G. and I.G.-F. All authors have read and agreed to the published version of the manuscript. **Funding:** This research received no external funding. **Data Availability Statement:** The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author. **Conflicts of Interest:** Author [PERSON] was employed by the company InnovaBiens-tar de Mexico, S.A.P.I. de C.V.