Effects of solution treatment on microstructure and mechanical properties of (SiC+TiB2)/Al–Zn–Mg–Cu composite fabricated by laser powder bed fusion

Abstract

This study investigated the effects of solution treatment (ST) on the microstructure and mechanical properties of (SiC+TiB2)/Al–Zn–Mg–Cu composite produced using laser powder bed fusion (LPBF). Microstructural analysis reveals that the grid-like distribution of eutectic precipitates within the as-printed composite disappeared, giving way to the formation of uniformly distributed precipitates. As the ST temperature increased, the content of spherical Si particles decreased, while the content of elongated Al4SiC4 precipitates increased. Matrix grains recrystallization occurred, resulting in a gradual increase in the average grain size from 3.79 μm to 5.23 μm. The preferred crystallographic orientation features along the printing direction, <001> {001} plate texture, were weakened, gradually exhibiting a more disordered growth. The microhardness and tensile strength of the composites exhibited a slight decrease and exhibited a trend of initially increasing and then decreasing with increasing ST temperature. Additionally, the heterogeneity in microhardness along different directions has been reduced. When the ST temperature was 460 °C, the elongation of the composite experienced a significant increase, escalating from 6.12 ± 0.36% to 10.3 ± 0.25%. However, with the increase in ST temperature, it displayed an obvious downward trend. The maximum tensile strength was 449 ± 8 MPa, and the elongation was 9.6 ± 0.4% with the ST temperature of 500 °C. The variations in mechanical properties were primarily attributed to the elimination of grid-like substructure, the uniform distribution of precipitates, and the gradual coarsening of grains. This research was expected to contribute to developing advanced lightweight materials with improved performance, opening up new opportunities for their application in various industries.