Orthogonal experiment and hardening mechanism investigation on the effect of heat treatment parameter on Sb-modified Mg2Si/Al-8Si composites

The Al-Si-Mg alloy is highly popular in the aluminum industry, and the Mg2Si/Al composites demonstrate extensive development prospects.However, the practical production of these composites still faces certain obstacles.In this study, L32(4 9 ) orthogonal experiments were conducted to systematically examine the impact of heat treatment conditions on 15% Mg2Si/Al-8Si composites with 0.5%Sb modification.The microstructures of the as-cast alloys and heat-treated samples were studied using OM, XRD, DSC, SEM, EDS, and hardness tests.By conducting an orthogonal test, the influence of each factor was analyzed to quantify its magnitude and identify the optimal heat treatment process.The results showed that the hardness value of the alloy could be increased from 74.77 to 163.86 HV through heat treatment.Additionally, the average particle size of the initial Mg2Si could be refined from 19.15 to 12.44 µm.Furthermore, the hardening mechanism of the heat treatment parameters was discussed in detail.K e y w o r d s : 15%Mg2Si/Al-8Si composites, orthogonal experiment, heat treatment, hardening mechanism Highlights-Among the nine factors considered in the designed orthogonal experiments, the secondary solid solution temperature and the secondary aging temperature had the greatest influence on the properties of the 0.5%Sb-metamorphosed 15%Mg 2 Si/Al-8Si alloy.The heat-treated alloy exhibited significant improvements, with the hardness value increasing from 74.77 to 163.86 HV and the average particle size of the incipient Mg 2 Si refining from 19.15 to 12.44 µm.-The optimized heat treatment process involves a primary solid solution temperature of 460 • C, a primary aging temperature of 60 min, a secondary solid solution temperature of 530 • C, a secondary solid solution time of 60 min, quenching in a salt solution, a primary aging temperature of 180 • C, a primary aging time of 180 min, a secondary aging temperature of 180 • C, and a secondary aging time of 120 min.