Pressurized solidification of semi-solid aluminum die casting alloy A356

Pressurized solidification behavior of semi-solid aluminum alloy A356 slurry in relation to the final microstructures and mechanical properties has been investigated. Sound semi-solid slurry has been produced, in which the primary alpha-Al presented in average diameter of 65 mu m and shape factor of 0.84. and featured zero-entrapped eutectic. The structural investigation revealed that application of pressure during solidification of semi-solid Slurry could decrease the grain size, improve the morphology of primary alpha-Al and modify the eutectic silicon due to increasing in the cooling rate. Furthermore, higher applied pressures increased the density and improved tensile properties. Subsequent T6 heat treatment raised the mechanical properties of A356 alloy to average values of tensile strength, 330 MPa, yield strength of 240 MPa and elongation of 13%. (C) 2009 Elsevier B.V. All rights reserved