Microstructure and Performance Evolution of Heat-Treated ZrO₂/AlSi10Mg Composites Processed by Selective Laser Melting

AlSi10Mg is the most commonly used aluminum alloy material for additive manufacturing, and its selective laser melting(SLM) products have been widely used in aerospace, automotive industry, and other fields. However, its low strength and plasticity limit its wide application. In this study, 0.3% (mass fraction) nano ZrO₂ particles are added to AlSi10Mg alloy atomized powder, and the ZrO₂/AlSi10Mg composite is formed by using the SLM technology. The microstructure, tensile property and anisotropic behavior are studied under different heat treatment regimes. The results show that when the annealing temperature rises from 180 ℃ to 270 ℃, the tensile strength decreases continuously, and the elongation first decreases and then increases. After being annealed at 180 ℃ for 2 hours, ZrO₂/AlSi10Mg show the best match of strength and plasticity, with the tensile strength of 481.74 MPa, the yield strength of 331.03 MPa, and the elongation of 8.5%. In the process of annealing treatment, the ZrO₂ ceramic particles in the composite material maintain a stable structure, and the phase transition is mainly the transition of the AlSi10Mg matrix. In addition, with the increase of annealing temperature, the proportion of large angle grain boundaries in the ZrO₂/AlSi10Mg composite material significantly increases, and the average local misorientation decreases. When the ZrO₂/AlSi10Mg composite is annealed at 180 ℃ for 2 hours, the tensile strength and elongation in the transverse and longitudinal sections are significantly better than those of the corresponding sections of the AlSi10Mg alloy.