Microstructure and Mechanical Properties of Spray Deposition Al/SiCp Composite After Hot Extrusion

Investigations of composite based on a spray deposition Al-Zn-Mg-Cu alloy reinforced with SiC particles with the volume fraction of 15% and various extrusion ratios of 11-39 are presented. Bars with a diameter of 8-15 mm were obtained as the end product. Based on the microstructural examinations of the composite, we can find that SiC particles adhered mainly to the surface of the alloy droplets during deposition, leading to more SiC particles at the surface of the droplets and less in the inner. Thus, the distribution of SiC particles in the billet was characteristic of the layered feature. This layered feature of SiC particles was not completely removed by the following hot extrusion. The SiC particles were distributed like the streamline in the longitudinal direction. A higher extrusion ratio resulted in an more uniform distribution of SiC particles. Ambient tensile tests made it possible to demonstrate that the mechanical properties improve with the increasing of extrusion ratio. The ultimate tensile strength and elongation achieve 475 MPa and 16.5% at an extrusion ratio of 39.