The Uniform Distribution of SiC Particles in an A356-SiCp Composite Produced by the Tilt-blade Mechanical Stirring

The tilt-blade mechanical stirring of A356-2.5vol.%SiCp liquid was conducted in a cylindrical crucible to solve the problem of nonhomogeneous radial distribution of SiC particles in conventional straight-blade mechanical stirring. The radial distribution of SiC particles in A356 liquid was studied under the conditions of 25° for horizontal tilt angle α of the blade, 200 r/min for rotating speed of stirrer and 10 mm/s for speed of moving up and down of stirrer. The results show that there exists a nonlinear relationship between circumferential tilt angle β of the blade and radial relative deviation d of SiCp content in A356 liquid. When β is smaller than 26°, the d of SiCp content in A356 liquid between the center and the periphery of crucible decreases with increasing β. Conversely, when β is bigger than 26°, d increases with increasing β. Only when β is about 26°, d can be equal to nought i.e. uniform radial distribution of SiC particles can be realized. It can be seen that the nonhomogeneous radial distribution of SiC particles in conventional straight-blade mechanical stirring can be eliminated in this tilt-blade mechanical stirring of A356-SiCp liquid.