JIN Yanwen, ZHANG Guangjie, CHENG Junfeng, ZHANG Shichao, ZHANG Benchang
In response to the demand for lightweight structural materials in aviation, aerospace, high-end electronics and other fields, the application of particle reinforced aluminum matrix composites has been rapidly developed. However, at present, most of the research on aluminum matrix composites focuses on the preparation and analysis of small and medium size ingot, and the research on large size ingot and its properties and microstructure is less. The hot pressing billets with the volume fraction of 15%, 20% and 25% SiCp, the matrix alloy of 2009Al and the size of ϕ580 mm×730 mm were prepared by powder metallurgy, and the extrusion rod was extruded to ϕ250 mm. The density of the extruded rods is 100%, and the particle distribution is uniform. A small amount of Al2Cu and Al7Cu2Fe are found by XRD analysis. The interface between SiCp and matrix was observed by TEM. It is found that SiCp and matrix are well combined, and no harmful interfacial reaction is observed. The tensile test at room temperature shows that the strength of the composite increases significantly with the increase of the volume fraction of SiCp. When the volume fraction of SiCp is 25%, the tensile strength of the composite is 630 MPa, the yield strength is 480 MPa, and the elongation is ≥3%. The tensile strength and yield strength of the composite are 20% and 25% higher than that of the matrix, respectively. The fracture modes of the three kinds of composites with SiCp content are dominated by the ductile fracture of the matrix alloy and the fracture of SiCp, and with the increase of the volume fraction of SiCp, the fracture phenomenon of SiCp increases significantly, and the fracture is more obvious, indicating that the high strength of the interface combination of SiCp and aluminum matrix makes SiCp plays a good bearing role.
