Thixoforming of spray-formed 6066Al/SiCp composites

Spray-formed composites of 6066Al/SiCp were thixoformed at different temperatures and the influences of temperature and ageing time on microstructures and formability studied. The experimental results showed that the grains coarsened slowly in the solid state, and quickly with increasing temperature and time in accordance with the Ostwald mechanism in the semi-solid state. The grains (or solid particles in liquid) remained equiaxed. Most large SiC particles were distributed in the liquid phase, while fine ones were in both solid and liquid phases. No apparent interfacial reactions were detected by SEM. The mechanical properties of 6066Al/SiCp made by semi-solid extrusion or squeeze casting were similar to those made by traditional casting followed by a forging process. The formability was excellent in terms of low forming force and capability of filling complex cavity.